CARLTON key defender Sam Rowe is confidently targeting a return in round one, 2018, after re-signing with the Blues.

Rowe told AFL.com.au on Thursday he thought his career might be over after he ruptured his right anterior cruciate ligament against Fremantle in round nine. 

The defender was due to come out of contract at the end of 2017 and was concerned that, at 29, his time at the elite level might be up. 

But Rowe said the Blues quickly reassured him he still had a future with the club, and the parties made it official this week when they inked a new one-year deal.  

"I had some strong assurances pretty quickly from the club that I would be offered a new contract, so they did settle my nerves fairly quickly," Rowe said. 

"Nothing's ever certain in footy but getting that reassurance from the club was quite comforting and just let me get stuck into getting the knee right and preparing myself for next year." 

Rowe's rehabilitation has been going "perfectly to plan" since he had a traditional knee reconstruction in late May. 

The former Murray Bushranger started running several weeks ago and is confident he'll be back playing in round one next season.

"The surgeons are pretty confident of that, especially because I didn't damage anything else in the knee apart from the ACL, which meant I could get going a lot quicker than some typical injuries," he said. 

"It is a very realistic goal to be up and going for round one next year and that's certainly what I'm aiming for." 

Rowe's injury occurred in highly unusual circumstances.

He initially came from the ground after Fremantle captain Nat Fyfe crashed across his right knee in a first-quarter smothering attempt. 

After being assessed on the boundary line, Rowe went back on to the ground about five minutes later with his knee strapped.

When the ball was kicked towards him on the wing soon after, he went to back into Matt Taberner. But after making slight contact with the Fremantle forward, his knee appeared to buckle and he fell to the ground. 

The Blues were quizzed after the game about whether Rowe should have been sent back after his collision with Fyfe, with coach Brendon Bolton and football chief Andrew McKay staunchly defending the club's medical team. 

Rowe, himself, has no concerns with how his injury was handled.

"I came off and I did all the tests after the first one and I was running and jumping and twisting and turning on the boundary and the doctors had a good feel of it and it presented pretty well. I was pretty keen to get back on that stage too, so we thought I would be right to go back on," Rowe said. 

"Then the second time I just kind of fell over. I know at the time there was a bit of speculation about whether I was treated properly, but I don't have any issues with how it happened.

"It is what it is. I was certainly keen to go back on and I don't think I was put in any further danger going back on, that's for sure." 

Rowe is, however, still at a loss to explain how his ACL ruptured. 

"My knee just clicked and I fell over. I remember being on the ground thinking, 'Hang on, why am I on the ground here? I didn't touch anyone, what's going on?' At that stage I thought something's not quite right," he said. 

Rowe said it was hard watching from the sidelines as the Blues won just one of their final 10 games.

But he was buoyed by out-of-favour forward Liam Jones' stunning transformation into a highly effective key defender in the second half of the season. 

Rowe was a mainstay in the Blues' defence from 2014 until his knee injury, finishing fifth in the Blues' best and fairest award in 2014 (when he was sixth in the AFL for one-percenters) and equal sixth last year (third in the AFL for one-percenters).

He knows Jones' successful move into defence will make the competition for spots in the Blues' back six tough in 2018, but welcomes the challenge.

"Every year there's always competition, especially in my role. Jonesy playing good footy in the back half of the year will make me a better player because I have to be a better player to get a spot in the team," he says.

"I think it is good for me. I'm looking forward to the challenge of improving and looking forward to playing some footy again next year."