Returning St Kilda defender Jake Carlisle predicts he won't hit the season in top form as he prepares to play his first game in 18 months.

Carlisle, 25, last took to the field as an Essendon player in the final round of 2015. He missed all of last year with a season-long doping ban as part of his time at the Bombers.

It has been a long wait, but Carlisle was excited to finally return, with his Saints debut to come against Melbourne on Saturday at Etihad Stadium.

He represented the Saints for the first time during the JLT Community Series, which saw him play all three games.

Carlisle told AFL.com.au it would take him some time to get used to the rigours of elite football.

"The first few weeks, body-wise, I think it will be a bit slow for myself to get into it full speed, but after that I think we'll be ready to go," Carlisle said.

Carlisle endured a rocky start to his St Kilda career. Just hours after his trade from the Bombers was finalised, footage emerged of him appearing to snort a white powder. The AFL handed him a two-game ban and an illicit drugs strike.

That suspension was rendered moot after the Court of Arbitration for Sport found 34 past and present Bombers guilty of taking a banned substance in January last year.

It meant Carlisle couldn't take to the field and help the Saints in their push for finals, which they missed on percentage only.

"I've got a lot to prove. Not only (to) the club, but the players and the sponsors and the supporters as well," he said.

"Compared to last pre-season, it was a bit tougher, coming in from a different environment and what had happened. I'm very happy now and I've adapted really well."

However, he was able to look at the positive side at being away from the game.

"It was a break that I needed, in a way. I've managed to do a lot of things over the break and it's just good to be back now," he said.

While hip and back injuries had caused him concern throughout his football career, the mental burden proved more troublesome.

"Obviously physically, I had surgery over the break as well and managed to get my body on point for this pre-season. The way I've fitted in with the program here has been managed really well," he said.

"Mentally, with what I've been through, it's obviously been tough.

"I am here now to put everything behind me and just move on, and obviously grow as a person and a player at a different club (in) a different environment."

Carlisle has been able to do leg exercises in the gym, which he hadn't been able to do previously because of back issues. They still cause him some grief but a specialised program means his problems are manageable.

Even though pre-seasons can typically be flat affairs for footballers, for Carlisle, it was a different experience.

"It's actually gone quick. It's been 17 or 18 months since I've played, so it feels like a big pre-season," he said.

"Managing to go away and enjoying myself and working outside of footy [in the construction industry] was definitely good mentally, because when I was able to come back, it's four or five months until round one and before you know it, it's already flown. As hard as pre-seasons are, I actually enjoyed this one."

Hip surgery last year took longer to recover from than expected as St Kilda took a conservative approach but he returned to full training at the start of the year.

"I wanted to do more (early in the pre-season) but at the same time, understood the program that I was on. Physically, it made my body adapt and react really well, so I was pulling up from sessions really well," he said.

"Come the first (JLT Community Series) game against Port (Adelaide) … the hip pulled up pretty good, so that's always a good sign. Going into round one, I feel pretty good."

Carlisle was recruited to bolster a backline that had been short on size but he could be sent forward if the situation demands.

The Saints have Josh Bruce, Tim Membrey and Paddy McCartin up forward, while Nick Riewoldt often floats down from a wing, but Carlisle's contested marking gives coach Alan Richardson another option.

A two-week period in 2014 saw him kick a combined 12 goals and take a mammoth 31 marks, highlighting his potential in attack.

"If we're three or four goals down at three-quarter time and things aren't working, it's always going to be a change of sneak forward or in the ruck or something," he said.

"It's obviously a good string in the bow to have but at the same time, I'm here to play defence and help the Saints be one of the best defensive teams in the comp."