FRESH off signing a one-year contract at St Kilda, rangy defender Sam Gilbert refuses to put a ceiling on how long his career can last.

Any time a player hits his 30s, the decision to keep him at the club becomes more difficult. But with the 31-year-old's speed and desire to compete yet to drop off, the Saints gave the Queenslander a chance to play a 13th season.

"When he doesn't play, we feel like there's a bit of a hole in the back half, because he's so versatile," St Kilda defensive coach Rohan Welsh told AFL.com.au.

"It doesn't really matter what the opposition throw at us from a forward point of view. He's played well on a Jeremy Cameron before, he's played well on a really small forward, like an Eddie Betts-type, so he can cover all bases."

Knee and foot injuries limited him to 26 games in 2013-15, but they haven't caused lingering issues. In fact, he told AFL.com.au they might have freshened him up.

"Sometimes when you miss a lot of footy, other parts of your body can become really good and less worn," Gilbert said.

The work Gilbert does in the backline to help his teammates is integral to the way the Saints play.

"He's one of those guys who reads the cues really early, looks to help his mates, leave his opponent and obviously get to the ball. That's something that we've really concentrated on a fair bit this year … and he's probably one of the better ones at that," Welsh said.

His move into the ruck was a sign of his versatility.

Being an older player, the coaches consulted Gilbert about taking on the arduous position and he had no hesitation.

"I'm almost banging down the door to see if I can be the second ruck. Sometimes down back, you're so opposition focused, so it's nice to get in the ruck and just play footy," Gilbert said.

The 197-game player worked with ruck coach Adam Skrobalak for a couple of weeks before being thrown into the action. At 194cm and 90kg, Gilbert is regularly outsized but thrives after the initial contest.

"Once the ball leaves the hand, probably of the opposition ruckman more times than not, I'm then hitting the ground and get to chase the ball and really tackle and harass," Gilbert said.

An abdominal strain suffered while laying a tackle against North Melbourne last week will sideline him for one game. Unfortunately for him, that clash against Richmond at the MCG on Sunday will almost certainly be the final match of the club's longest-serving skipper in history, Nick Riewoldt.

Being able to send off the six-time Trevor Barker Award winner appropriately after the Roos game provided some consolation.

"It's strange to think that chairing off a champion can give you so much satisfaction," Gilbert said.

St Kilda is well stocked for young backmen, with Brandon White, Daniel McKenzie and Bailey Rice named as emergencies against the Tigers.

While they would be expected to compete for spots in the senior side next year, Welsh pointed out Gilbert's adaptability will make him hard to drop.

"I think that's the thing that's going to keep him at the club longer than what it's not," Welsh said.

A career in carpentry awaits Gilbert when he finishes up with football, but he hopes that doesn't come for some time yet.

"I don't see next year as my last year. But you know, it's not in your court all the time. I've just got to live up to my part of the bargain and prepare well and play the best footy I can," he said.