VETERAN North Melbourne defenders Michael Firrito and Scott McMahon are far from spent forces despite their difficult 2013 seasons, Scott Thompson says.

 

McMahon and Firrito started last season as almost automatic selections in North's backline, but were relegated to the VFL late in the year because of injury and inconsistent form.

 

Firrito was dropped after North's round 16 loss to the Brisbane Lions, with McMahon joining him in the VFL a week later after the Roos' round 17 loss to Carlton.

 

Firrito fought back to play North's final two games, but McMahon spent the remainder of the year with Werribee.

 

Thompson told AFL.com.au the competition for spots in the Roos' defence had never been fiercer in his seven years at the club.

 

North's already solid backline depth was bolstered in the off-season with the acquisition of father-son recruit Luke McDonald and key-position rookie Joel Tippett, while former St Kilda star Nick Dal Santo is also expected to spend time at half-back this year.

 

However, Thompson said Firrito, 30, and McMahon, 27, should not be pensioned off just yet.

 

"Michael Firrito and Scotty McMahon have been going really well this pre-season," Thompson said.

 

"'Spud' (Firrito) got injured and went out of the team last year, but he had a good finish to the year. He came back in for the final two games and had a tough couple of weeks playing on Travis Cloke and Lance Franklin, but I thought he played really well.

 

"And Scotty has had probably one of his best pre-seasons so far. He's training really well and he's just a natural footballer.

 

"So I expect to see both of those guys bounce back this season."

 

Fellow defender Nathan Grima, 28, has not enjoyed the same good health as Firrito and McMahon this pre-season.

 

After an operation on his left foot in September, Grima has again battled back soreness this summer.

 

But the Roos are expecting Grima will return to play some part in their NAB Challenge campaign, and Thompson believes if anyone can overcome a limited pre-season it's his fellow key defender.

 

"First of all, 'Narni' (Grima) is a terrific player – I rate him as one of the best defenders in the competition," Thompson said.

 

"He's had a few niggles this pre-season but he's probably one of our best runners at the club and one of the fittest, so he's someone who can miss a few sessions and come straight back into it."

 

Thompson also had a delayed start to his 2014 pre-season after having minor surgery on his left knee at the end of last season.

 

The 2013 All Australian full-back has also had to monitor the bruising he suffered to his lungs when he landed awkwardly on his back after a marking contest in North's round 20 loss to Adelaide.

 

Thompson said he would have a final scan of his lungs next week as a precaution, but stressed he was carrying no side effects from the injury and was back in full-contact training.

 

"I was back into full training just before Christmas, so I only missed three or four weeks of the pre-season," he said.

 

"All the scans (on my lungs) have shown heaps of improvement, so I'm confident I've fully recovered and I'm right to play."