HE'S NEARLY the last man standing.

Richmond premiership defender Dylan Grimes is one of just two first-choice Tiger defenders who haven't been struck down by injury at some point this season.

Alex Rance (ACL in round one), Jayden Short (dislocated elbow in round three), David Astbury (ankle in round six) and Bachar Houli (missed rounds 2-4 with a hamstring strain) have all spent time on the sidelines this season.

Nick Vlastuin (ankle) is also in doubt for Sunday's match against Fremantle.

It means Grimes, who missed round three through suspension, and teammate Nathan Broad have been the mainstays of the team's decimated backline this season.

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"It's been a challenge, but a learning opportunity for me. In some ways, it's the best thing that could have happened for my game, in the sense I'm forced to grow and change and play a completely different role to what I'm used to," Grimes told AFL.com.au.

"To be honest, we sort of started that process even when Alex (Rance) was there, the plan was to maybe get him a little bit further up the ground. For me, it's been equally challenging and rewarding to develop a different side of my game.

"Having Dave (Astbury) and myself down as the deepest players is a different look, but I'm really enjoying it."

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The 27-year-old has been a model of consistency since overcoming the hamstring issues that affected the first portion of his career and is growing in confidence with greater responsibility.

"Having all the team in front of me and communicating and trying to set our team defence up behind the ball has been slightly different," Grimes said.

"But I think there's a whole number of skills I've had to learn. Last year I was playing mainly on smaller players, this year I'm finding myself more on key (position).

"So, there are those aspects, but in terms of leadership, Rancey's left a big hole. But collectively as a back seven everyone's taken a bit of a step forward in that role. It's not like it's been all on my shoulders, it's been spread across a huge number of leaders."

One of the surprise stars of Richmond's topsy-turvy season has been Sydney Stack, who was passed over in the NAB AFL Draft, trained with the club over the pre-season and was signed in March during the Supplemental Selection Period.

Stack has slotted into the backline with ease, his confidence and decision-making belying his age of 19.

"He's come in the back door, in some ways, into the club. We saw pretty early on that he had some talent and in pre-season he was a very clean player, that stood out," Grimes said.

"Then one thing we didn't really get a gauge on until games started was how tough he was and how much flair he plays the game with. He's another young player who has come on in leaps and bounds.

"I think the exciting thing about Syd is that his best footy is still to come. At times you forget him and Jack Ross and Noah Balta have only played three to five games, they're definitely exciting prospects for our footy club."

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Fremantle and its tall forward line spearheaded by recruit Jesse Hogan poses a different challenge to the nippy Tigers.

Despite questions over the fitness of Astbury and Vlastuin, Grimes has been preparing as if the pair will play.

"From a backline perspective, we've certainly got our work cut out for us. The challenge of going over there, the big ground and the speed that they play the game with is going to be something we'll have our focus on.

"We always plan for everyone to play and if they're on the cusp, we start with them in the side and then see what happens after that. Our preparations remain relatively similar to other weeks.

"Obviously, I'd love to see both of those guys out there because they make my job a hell of a lot easier," he added with a laugh.