VETERAN defender Jared Rivers has announced his immediate retirement due to chronic knee problems.

The 30-year-old ends his AFL career having played 194 games across 13 seasons for Geelong and Melbourne.

"I've got mixed emotions, of course," Rivers told geelongcats.com.au after informing his Cats teammates of his decision on Monday.

"In the end it was a bit of an easy decision, knowing that I physically can't go on anymore. The knees have finally won and I've had to pull up stumps a bit earlier than what I would've liked.

"But that's just what happens sometimes in footy, unfortunately, so I'm a bit sad about not being able to run out on the 'G again."

Rivers suffered yet another knee injury in Geelong's round 20 loss to Hawthorn at the MCG.

He played out the game, to the amazement of the Cats' medical staff, but scans later showed a torn meniscus.

"After I felt it, I knew it was going to be my last game," Rivers said. "So at half-time I got a bit of help from the doc to get me through the second half.

"It was a bit sore, but you just push through those things knowing that it's going to be your last game.

"It was a big game against the Hawks in front of 50,000 at the 'G, so I suppose I can be thankful that my last game was a big one.

"We didn't get the result we wanted, of course, but running out with the boys one last time is something I'll always remember."

Rivers, who grew up in the South Australian town of Port Augusta, began his AFL career at Melbourne in 2003. He blossomed under the coaching of Neale Daniher, taking home the NAB Rising Star award in 2004.

"Winning that award was a really proud moment," he recalled. "It was something I never thought would happen.

"I had a great time at Melbourne in those early days, and I'm still close with a lot of the older boys – the likes of David Neitz, Adem Yze, Cameron Bruce and Brad Green – who were there when I started.

"To play alongside them, given they are greats of the Melbourne footy club, was a great experience. And we had a bit of success, playing in a few finals games, so it was a great start.

"I still speak to Neale every now and then. He was a country boy and so was I, so he was great for me."

After 150 games with Melbourne, which yielded just 54 wins (24 of them came in just two seasons in 2004 and '06), Rivers moved to Geelong in the lead-up to the 2013 season.

He was sidelined by injuries for a large chunk of his first year at the Cattery, but fought his way back into the team for the finals.

And he was in the thick of the action during the heartbreaking five-point loss to Hawthorn in the 2013 preliminary final.

Rivers played 22 games last season, including both of the Cats' finals, and rounded out his career with another 12 AFL appearances this year.

"I went there to win a premiership, and I got close but didn't quite get there," Rivers said.

"But to have the opportunity to play in a few finals and play alongside some great players at the Cats, I couldn't be happier.

"I feel lucky to have played for the two oldest clubs in the competition. I couldn't have picked two better clubs to play footy for."

Rivers remains on very good terms with many people connected with the Melbourne footy club, and he has been among the most popular players at Geelong during his time there.

"Building relationships has been one of the highlights of my career," he said. "I've got to know and play alongside so many great people.

"And that's the thing I'm going to miss most: just rocking up each day and spending time with my best mates."

Knee soreness was a constant for Rivers during the latter part of his career.

"Towards the end I felt like I was running out hoping I could stay together, whereas I should've been thinking about playing footy," he said.

"If you're worrying so much about your body at the age of 30, you just can't go on. I didn't want to be letting my teammates down."

Rivers, who turns 31 in October, ended up playing 44 games for Geelong.

As for the future, he is undecided about what he'll be up to next year. Rivers will continue working with the club’s coaching staff for the remainder of the 2015 season to continue his development off the back of completing the Next Coach Program in 2014

"I'd love to stay in the AFL system, whether that's in a development role or a coaching role," he said.

"I've done a bit of that work over the last few years with Xavier College and helping out the young boys here at Geelong.

"I've enjoyed that side of the game and I still love footy, so if I can stay involved in some way that would be great. I think I've got a lot to give."

When it comes to the outlook for Geelong, Rivers will depart Simonds Stadium confident that the Cats have a bright future in front of them.

"They've got a really good core group that can go on and contend," he said.

"No doubt the footy club will look to bring a few people in as well to help with that, but there's some great young players pushing up, with Jake Kolodjashnij playing well and Darcy Lang and Jackson Thurlow.

"It's amazing how Geelong keeps going. People write the Cats off all the time, but the way the club keeps itself in contention is quite remarkable."