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ADELAIDE'S forward line will be further stretched by the loss of goalkicker Mitch McGovern, who is expected to miss an extended period with a right hamstring injury.

The 22-year-old pulled up sharply in the final quarter of Saturday night's Showdown against Port Adelaide after sprinting to compete in a one-on-one marking contest near the boundary line.

McGovern limped off the ground and did not return, with scans to determine whether he suffered a high-grade hamstring tear.

The fitness of key forward Josh Jenkins will be a topic of conversation this week after he failed a fitness test ahead of the Showdown.

The 28-year-old had difficulty breathing following the elbow he received to his left ribs from Hawthorn youngster Teia Miles in round two, but was later cleared of structural damage to his ribs or internal organs.

Jenkins sustained bruised ribs in the heavy collision.

A surgeon will on Monday decide whether Melbourne ruckman Max Gawn requires surgery after scans confirmed his right hamstring injury is worse than initially thought.

The 25-year-old contested a centre bounce during the second quarter against Geelong, followed up his tap work and attempted to tackle Cats skipper Joel Selwood, only to pull up lame after sliding to ground.

The club anticipated Gawn's recovery time would be longer than a standard four-week hamstring injury after scans on Sunday revealed tendon damage.

Gawn immediately signalled to the bench for assistance following the incident and hobbled off the ground from the centre square.

Greater Western Sydney midfielder Ryan Griffen also looks set for an extended stint on the sidelines after picking up a left ankle injury during the second quarter against North Melbourne.

The 30-year-old limped heavily from a contest at half-forward just before half time.

Griffen took no part in the second half and had ice applied to his injured lower leg, before leaving the ground on crutches and in a protective moon boot.

Giants coach Leon Cameron described Griffen's injury as "nasty".

Griffen had earlier received a cut above his left eye in the first quarter and returned to the field with a bandaged head.

Compounding matters for the Giants, co-captain Phil Davis was left with a sore left shoulder following a high-impact collision with Kangaroos captain Jack Ziebell in the final quarter.

Davis hurt the AC joint in his shoulder in the incident, although the Giants were hopeful the concern was not too serious.

Western Bulldogs midfielder Liam Picken was heavily concussed after receiving an accidental elbow to the face from Fremantle's Tommy Sheridan in the second quarter.

After the initial elbow contact, Picken's head became sandwiched between Sheridan's hip and the ground as he landed.

The 30-year-old lay motionless for about 30 seconds, before walking off gingerly with the assistance of trainers.

Picken watched the second half from the bench and looked in good spirits.

Richmond defender Nick Vlastuin was left dazed after receiving an accidental forearm to the head from West Coast's Brad Sheppard in the third term.

The 22-year-old was bleeding from his nose and sat out the rest of the match after failing a concussion test at three-quarter time.

On Saturday, Tigers coach Damien Hardwick expected Vlastuin to "bounce back and be right for next week".

In other injury concerns in round three:

- Melbourne defender Bernie Vince underwent a surgical procedure on Saturday night to repair a toenail injury he suffered against Geelong. The 31-year-old had his foot stomped on, but managed to get through the game with the help of the medicos.

- Hawthorn small forward Paul Puopolo appeared to injure his hamstring against Gold Coast and was assessed in the rooms.

- Brisbane Lions defender Darcy Gardiner suffered a corked right quad in the first quarter against St Kilda. The 21-year-old had ice applied to the affected area and played no further part in the match.

- Carlton swingman Jacob Weitering received a heavy bump from Essendon's Patrick Ambrose in the second quarter. The impact then saw the young Blue clash heads with Bomber Michael Hurley. Weitering came off under the blood rule and returned after an extended spell on the bench, while Hurley remained on the ground and, like Weitering, passed a concussion test.

- St Kilda defender Dylan Roberton received a heavy knock to his shoulder in the final quarter against the Lions, but managed to return to see out the final minutes of the match.

- Geelong defender Zach Tuohy appeared to hurt his right shoulder after being on the receiving end of a heavy bump from Melbourne's James Harmes in the third quarter.

- Geelong superstar Patrick Dangerfield received treatment on his right groin in the last term, but returned to the field and got through without any major problems.

- West Coast forward Mark LeCras received an accidental knee to the back of his head from Richmond's Jayden Short in the final quarter. LeCras came off under the blood rule, but returned to feature in the closing stages.

- GWS midfielder Josh Kelly hurt his ankle early against North Melbourne, but showed no signs of the niggle throughout the game.

- Geelong pair Mark Blicavs and Lachie Henderson collided into each other head-first in a friendly fire incident in the third quarter. Blicavs kept playing, while Henderson left the ground but returned soon after.