Best key defender: Daniel Talia; 15 matches; 24 goals conceded; 1.66 goals conceded every 120 minutes
No surprise that the reigning best and fairest has been the Crows' best key defender this year. He's lost less than a quarter of all one-on-one battles he's engaged in (21.3 per cent) and has been the general in a very young backline. He's conceded more goals than any other Adelaide defender (24) but given he's assigned the opposition's most dangerous key forward each week, conceding fewer than two goals a game is a classy result.

Best mid/small defender: Rory Laird; 16 matches; 13 goals conceded; 0.96 goals conceded every 120 minutes
Like Talia, Laird is a standout defender at West Lakes. He has improved his offensive game dramatically this year, leading to high possession numbers and great offensive drive. But he has maintained his defensive reliability too, conceding less than a goal a game. Of Laird's 22 one-on-one contests this year he has lost just five – showcasing why he is being touted as a possible All Australian in 2015. - Harry Thring

Best key defender: Harris Andrews; 14 matches; 22 goals conceded; 1.63 goals conceded every 120 minutes
It's been an incredible first season for the Lions Academy product, who was rewarded this week with a NAB AFL Rising Star nomination. There must be a disclaimer in these numbers that Andrews played his first handful of games as a key forward, but even factoring that in, he's the Lions' best key post man in 2015, losing just 10 of his 36 one-on-one contests (27.8 per cent). A special mention goes to Justin Clarke, who is conceding just 2.36 goals per 120 minutes, despite almost always getting the best forward.

Best mid/small defender: Marco Paparone; 17 matches; 19 goals conceded; 1.22 goals conceded every 120 minutes
Paparone has been a quiet achiever this season, finding a home as a third tall or running defender. He has lost just 28 per cent of his one-on-one contests, which would surprise many considering his lighter frame. Jed Adcock was also his reliable self, conceding just 13 goals for the season before being switched to the forward line after the bye. - Michael Whiting

Best tall defender: Simon White; 13 matches; 22 goals conceded; 1.98 goals conceded every 120 minutes
After starting the season in a run-with role in the midfield, White was forced to return to defence with vice-captain Michael Jamison on the sidelines for two months with a calf injury. Under constant pressure he has punched above his height and weight on numerous key forwards, including big Swan Kurt Tippett. In 13 games he has been involved in 48 one-on-one contests, losing only 13 of them (27.1 per cent) and conceding only 22 goals.

Best mid/small defender: Sam Docherty; 15 matches; 19 goals conceded; 1.38 goals conceded every 120 minutes
Docherty has plugged away and shown leadership in the face of adversity in the long-term absence of Jamison and with Sam Rowe filling holes all over the ground. He possesses fine judgment and has shown he is prepared to take a few risks to create a scoring opportunity. In 15 games he has conceded only 19 goals, is third at Carlton for intercept possessions (82), fourth for kicks (205) and fifth for uncontested possessions (215). - Howard Kotton 

Best key defender: Nathan Brown; 17 games; 20 goals conceded; 1.31 goals conceded every 120 mins 
The 2010 premiership defender has played every game and spent more time on the field than any Pies backman, losing just 10 (17.5 per cent) of his 57 one-on-one contests – fifth in the AFL among key forwards. The 26-year-old, 110-gamer is a reliable percentage player who uses his experience to cut the angles, is solid defensively in the air and deceptively quick to close on leading opponents. His season high point was a round 11 obliteration of Giants star Jeremy Cameron.

Best mid/small defender: Marley Williams; 16 games, 14 goals conceded; 1.05 goals conceded every 120 mins 
The most impressive aspect of Williams' appearance as a leader in this category is that while he rarely allows opposition small forwards to score on him, he has still managed to be an attacking backman with his pace, dare and penetrating left foot. This speaks volumes for his decision-making and ball use – two of the elements that have let the Pies down during their six-game losing streak (a nine-year low). A fierce competitor, he has lost just three (14.3 per cent) of his 21 one-on-one contests – fourth in the AFL among defenders. - Ben Collins

Marley Williams is enjoying perhaps his finest year off half-back for Collingwood. Picture: AFL Media 

Best key defender: Michael Hurley; 16 games; 20 goals conceded; 1.31 goals conceded every 120 minutes
It should be no surprise that Hurley leads the Bombers in this category, given he is one of the obvious candidates to feature in the All Australian team this year. His physical approach to the contest, combined with his smarts in the air and fierce attack on the ball, has seen him reach career-best form. In 16 games he has been involved in 54 one-on-one contests and lost just 11 of them.

Best mid/small defender: Mark Baguley; 17 games; 18 goals conceded; 1.15 goals conceded every 120 minutes
Baguley's intelligent and disciplined defending often goes unnoticed, but his value to the Bombers has been recognised in recent seasons. It's also reflected in the statistics, with the small defender often taking on the opposition's best small forward and limiting his influence. In one-on-one battles he had also been hard to get around, losing just 19.4 per cent of his contests. You need to be quick on your feet when you're a tight-checking defender, and Baguley plays his role well. - Callum Twomey 

Best key defender: Michael Johnson; 10 matches, seven goals conceded; 0.80 goals conceded every 120 minutes
The 2013 All Australian defender has changed roles this season to play as the second key defender due to the absence of Zac Dawson and Alex Silvagni. In his 10 games before suffering a hamstring injury he only lost eight one-on-one contests out of 34 (23.5 per cent) and conceded just seven goals. He is fractionally ahead of Luke McPharlin who has lost 25.9 per cent of one-on-ones and conceded 0.84 goals per 120 minutes. 

Best mid/small defender: Clancee Pearce; 15 matches, four goals conceded; 0.33 goals conceded every 120 minutes
Pearce has played more in the midfield this year, hence his defensive stats for goals conceded look very good. Another midfielder/half-back Tommy Sheridan has conceded 0.53 goals per 120 minutes. Of the full-time defenders, Paul Duffield has conceded just seven goals in 12 games but currently finds himself out of the side. Lee Spurr, the Dockers' No.1 small defender, has allowed just 13 goals in 16 matches. - Alex Malcolm

Best key defender: Jared Rivers; 11 matches; 15 goals conceded; 1.49 goals conceded every 120 minutes
If Rivers had not been so hampered by a lingering knee injury, the key defender would likely have been a permanent member of Geelong's backline in 2015. Rivers has lost just five of his 31 contests this season, largely due to his ability to affect spoils even when caught out of position. At present, the 30-year-old, who is almost certain to retire at the end of this season, is being held out of the side by emerging youngster Jake Kolodjashnij.

Best mid/small defender: Jackson Thurlow; 14 matches; seven goals conceded; 0.57 goals conceded every 120 minutes
Thurlow has excelled as one of Geelong's leading distributors off half-back in 2015, but the 21-year-old's ability to keep his opponent in check has gone largely unnoticed. Thurlow, who is deceptively rangy at 190cm, can play on talls and smalls, with his powerful vertical leap allowing him to spoil or take intercept marks. ­- Ben Guthrie

Best key defender: Steven May; 13 matches; 31 goals conceded; 2.50 goals conceded every 120 minutes
May has had another super season. Without a full strength midfield for much of the year, the Suns' defence has been under-siege, and May has stood firm. Always getting the best forward, he has lost just 12 of his 50 one-on-one contests (24 per cent). Henry Schade has improved dramatically in his fourth season at the club, and despite losing a higher percentage of his contests, has conceded just 1.84 goals per 120 minutes.

Best mid/small defender: Adam Saad; 13 matches; 12 goals conceded; 1.06 goals conceded every 120 minutes
There's a hair between Saad and Kade Kolodjashnij and you could argue for either as having a better year. Saad's numbers are terrific, as he not only provides dash from the back half, but a sound defence, losing just four one-on-one contests all season (17 per cent). Kolodjashnij has had no second-season blues, losing just six of his 20 contests and conceding 0.76 goals per 120 minutes. - Michael Whiting

Adam Saad has been a remarkable find for Gold Coast in his debut season. Picture: AFL Media 

Best key defender: Phil Davis; 10 matches; 10 goals conceded; 1.13 goals conceded every 120 minutes
The co-captain would have been in All Australian discussions before he went down with an ankle injury in round 11, costing him five games. Davis usually asks for the toughest job each week, which has seen him take on the likes of Lance Franklin, Travis Cloke and Nick Riewoldt. From 47 one-on-one contests this season the Giant has lost just 13, and provides the young GWS defence with a cool head under pressure.

Best mid/small defender: Matt Buntine; 11 matches; 6 goals conceded; 0.67 goals conceded every 120 minutes
Buntine might be underrated by those outside the club but is a vital part of the Giants' backline. Injuries to Patfull and Davis mid-year forced the 21-year-old to take on bigger opponents but the old-fashioned, dour defender has risen to the challenge. The 2011 No.5 NAB AFL Draft pick can play on smalls and talls and is developing the offensive side of his game steadily. - Adam Curley

Best key defender: Josh Gibson; 16 matches; 21 goals conceded; 1.31 goals conceded every 120 minutes
These figures underline why Gibson is one of the most important players at Hawthorn. In a full-strength side he is actually the third defender because Brian Lake and either James Frawley or Matt Spangher take the key opposition talls, but Gibson's reach and his excellent spoiling ability make him an integral part of the Hawk back six and he will be a key figure in September. 

Best mid/small defender: Ben Stratton; 16 matches; 20 goals conceded; 1.32 goals conceded every 120 minutes
Stratton's ability to play short and tall – as well as his contested marking – contribute to him being a key defensive weapon for the Hawks. Eddie Betts, Michael Walters and Jamie Elliott have been three of his key scalps of late and while he doesn't do a whole lot with the ball when he gets it, as long as he puts the clamps on a dangerous opposition forward, he remains one of the first picked at the Hawks. Mark LeCras this week? - Ashley Browne

Best key defender: Lynden Dunn: 17 games; 28 goals conceded; 1.72 goals conceded every 120 minutes
The vice-captain started the season slowly but has hit his straps as the year has worn on. It has been important, as it has allowed Tom McDonald to spend time forward after he struggled for a couple of weeks (McDonald has conceded 33 goals) and confirmed Dunn as a reliable, experienced player now. Very good in one-on-one contests, Dunn is strong and confident enough to direct his teammates.

Best mid/small defender: Heritier Lumumba; 16 games; 14 goals conceded; 0.97 goals conceded every 120 minutes
Lumumba splits the middle between Daniel Cross and Neville Jetta for goals conceded per minute, and arguably Jetta is the only true defender of the trio. However Lumumba pushed back off the wing when the Demons came under pressure at various points during the season and continued to counter-attack. His presence will be important when Christian Salem returns from injury next season. - Peter Ryan

Best key defender: Robbie Tarrant: 15 matches; 20 goals conceded; 1.45 goals conceded every 120 minutes
Tarrant has been a revelation since moving into defence this season. The 26-year-old has regularly been assigned the opposition's most dangerous power forward and has held his own against stars such as Tom Hawkins, Jarryd Roughead and Travis Cloke. Of 44 one-on-one contests this season, Tarrant has lost just 14.

Best mid/small defender: Shaun Atley: 15 matches; nine goals conceded; 0.71 goals conceded every 120 minutes
North has long looked to Atley to take on he game from half-back, but the fifth-year defender has become an increasingly stingy backman in recent seasons. Teams previously tried to exploit Atley by isolating him with his opponent deep inside North's defensive 50, but the 22-year-old is now far stronger in one-on-one contests. His speed also means that opponents struggle to get away from him on the lead. - Nick Bowen

Shaun Atley has added rock-solid defence to his natural attacking flair. Picture: AFL Media

Best key defender: Jackson Trengove; 13 matches; 15 goals conceded; 1.31 goals conceded every 120 minutes
The big, aggressive key back has been outstanding for the Power this season despite missing some footy through injury. He has lost just eight of his 55 one-on-one contests (14.5 per cent), a sign of his skill and determination to win. Trengove is a vital cog in Port's side both for his output and his on-field leadership and is ultimately irreplaceable. The constant pressure on him to hold strong only further highlights how important Trengove is.

Best mid/small defender: Matthew Broadbent; 16 matches; five goals conceded; 0.35 goals conceded every 120 minutes
Although he plays his footy further from goal than, say, Jarman Impey or Cam O'Shea, Broadbent has been one of the side's stingiest defenders this year. He has conceded just five goals at less than half a game – far better than any other backman at Alberton. He's leading the club for rebound 50s, generating 14 more than Jack Hombsch despite playing one fewer game. - Harry Thring

Best key defender: Alex Rance; 17 matches; 19 goals conceded; 1.15 goals conceded every 120 minutes
The 25-year-old has emerged as the game's best key defender this season and an All Australian lock. Shuts down the AFL's best, such as Lance Franklin, and attacks when he can, averaging 3.1 rebound 50s. Of the 78 contests Rance has been engaged in, he has lost only 15. Appears settled since signing a new four-year deal with the Tigers.

Best mid/small defender: Jake Batchelor; 17 matches; 16 goals conceded; 1.14 goals conceded every 120 minutes
Viewed as a developing player at the start of this season, Batchelor has become a key cog in the Tigers' back six as a third tall defender. Somewhat of an unsung hero, his athletic ability means he matches up on difficult players to contain, such as Giant Cam McCarthy, who he held goalless in round 14. He doesn't win as many offensive possessions as he could, but he is doing the job defensively. - Nathan Schmook  

Best key defender: Sam Fisher; 13 matches; 23 goals conceded; 1.97 goals conceded every 120 minutes
The 33-year-old has enjoyed a better run this season after two injury-hit years and continues to get the job done on some of the game's best forwards. Fisher has only lost nine of 32 one-on-one contests and conceded just 23 goals, while also playing a mentoring role for Hugh Goddard and deconstructing match vision with the first-year defender. Whether Fisher will play on next year is unclear, but the 211-game veteran should be pleased with his form in the twilight of his career.

Best mid/small defender: Shane Savage; 16 matches, five goals conceded; 0.41 goals conceded every 120 minutes
Found a new lease on his career as a dashing half-back last season after being dropped to the VFL and the former Hawk has built his standing to become a valuable member of the exciting young Saints under Alan Richardson. Seen mostly as an attacking defender, with his long-kicking and eagerness to take the game on (second at St Kilda for running bounces), Savage has also been able to lock down on dangerous small forwards and has only had five goals kicked on him this year. - Travis King

Sam Fisher has returned to his best after struggling with injury in recent years. Picture: AFL Media

Best key defender: Sam Reid; 16 matches; five goals conceded; 0.34 goals conceded every 120 minutes
Reid is part of an experienced Swans defence that has had its challenges in 2015, but the 23-year-old has been a consistent performer. The 2012 premiership forward has spent time at both ends of the ground this season, but has conceded just five goals. Reid looks set to finish the year inside forward 50 but looms as an important swingman over the next five games and during the finals. Heath Grundy has been the mainstay for the Swans and has lost just 15 of 72 one-on-one contests for the year, playing on the competition's best key forwards.

Best mid/small defender: Jarrad McVeigh; 16 matches; six goals conceded; 0.42 goals conceded every 120 minutes
The veteran has provided the Swans with plenty of run off half-back and although he's been used in a variety of roles in 2015, the Swans look at their best when the co-captain is orchestrating their attacks from defence. McVeigh averages almost 24 possessions per game at 82 per cent efficiency this season and has also kicked eight goals, showing just how valuable he is to coach John Longmire. Rhyce Shaw's stats stack right up with those of his co-captain; the dasher has given up just six goals from 17 matches. - Adam Curley

Best key defender: Jeremy McGovern; 14 matches, 15 goals conceded; 1.25 goals conceded every 120 minutes
The youngster has become one of West Coast's most important players following the early season losses of Eric Mackenzie and Mitch Brown. The Eagles play a system defence, so their man-on-man stats might not be as telling as other clubs. McGovern has conceded 15 goals in 14 matches while Will Schofield has played as the deeper defender and has conceded 26 goals in 16 games. McGovern has lost 26 per cent of his one-on-ones while Schofield has a better record, only losing 15 of his 63 one-on-one contests (23.8 per cent). 

Best mid/small defender: Sam Butler; 11 matches, six goals conceded; 0.61 goals conceded every 120 minutes
The veteran is statistically the best at West Coast for goals conceded but he plays more as a distributor from the back half rather than as a pure defender. Brad Sheppard has had an outstanding year and would arguably be the best mid/small defender. He has conceded just 11 goals in 17 matches (0.72 per 120 minutes). He's also lost just five of his 24 one-on-one contests. - Alex Malcolm

Best key defender: Fletcher Roberts; 10 matches; 14 goals conceded; 1.50 goals conceded every 120 minutes
The vastly improved 22-year-old has evolved into a best-22 player in 2015 and that has allowed the Dogs to play Jordan Roughead in the ruck and up forward. Roberts has lost only 11 of 32 contests he's been involved in this season. He is also a very good user of the footy with the league's sixth-best disposal efficiently of 87 per cent

Best mid/small defender: Dale Morris; nine matches, nine goals conceded; 1.21 goals conceded every 120 minutes
It should come as no surprise that Morris is the Bulldogs' most dependable defender, but statistically, he's also the AFL's best. The 32-year-old All Australian has remarkably lost only two of the 22 contests he's engaged in across nine matches this season. The 202-game veteran's ability to play tall or small gives Luke Beveridge great flexibility - Ryan Davidson

Dale Morris is enjoying a fine season after returning from injury. Picture: AFL Media