The veteran defender had the option of walking out on the Saints as an unrestricted free agent next month but he will now be a Saint until at least the end of 2017.

Knee, foot and groin injuries have restricted Gilbert to just 25 games in the last three seasons.

However, the 29-year-old has missed just one game since returning to the senior line-up in round 11 this year.

"After a bit of time on the sidelines, I'm enjoying my football as much as I ever have," Gilbert said.

"I'm looking forward to continuing to be involved for at least the next two years and seeing what this team can achieve.

"Obviously there has been a lot of improvement right across the board at the club in 2015 and I am very excited about what is ahead of us."

Coach Alan Richardson paid tribute to Gilbert's perseverance through some tough times.

"We have an exciting group at the club now and a lot of young players basically starting out on their AFL journeys. They can learn a lot from the examples set by Sam," Richardson told St Kilda's website.

"The persistence and determination he has shown in coming back from long-term injury to re-establish himself as a key part of our team is a testament to his character.

"It took him a little while to get back to full form and fitness following his injury but, over the past few weeks, he has reminded everyone of what a talent he is."

Gilbert was drafted by the Saints with pick No.33 in the 2005 AFL draft and, since debuting in 2006, has played 156 games including three unsuccessful grand finals in 2009 and 2010.