GEELONG defender Tom Lonergan has backed veteran teammate Jimmy Bartel to retain his spot in the side despite question marks around his form and ageing body.

Lonergan also said fellow defender Lachie Henderson, who has recovered from a knee injury, would be available for selection for the club's preliminary final clash against either the Sydney Swans or Adelaide at the MCG on Friday week.

Bartel, 32, played a defensive forward role on Hawks playmaker Josh Gibson in the club's thrilling two-point qualifying final win, but at times appeared susceptible to Hawthorn's fast-paced ball movement.

"He's been a fantastic player for us and he proved in that last game against Melbourne that he's still got a lot to offer and he's cool and calm under pressure in the big games," Lonergan said on Wednesday.

"We think he's a great part of our team, so I hope he's there in preliminary final week.

"We all love playing with him, but we'll leave it to the coaches to make that call."

Henderson, who had surgery on his knee after the game against the Brisbane Lions in round 22, trained fully on Tuesday and "is raring to go" against the Swans or Crows. 

The versatile defender is an automatic selection, meaning one unlucky player who played in the Cats' win over the Hawks will have to make way. 

"He trained yesterday and by all reports his knee is fine so he should be available," Lonergan said. 

"He'll be great for our structure, no matter where he plays. 

"If he's forward or back, he's a quality player, and he's had a terrific year, so it'll be great to get him back and he's fit and raring to go." 

Lonergan was outstanding against the Hawks, particularly late in the game when he took a number of relieving marks in defence, but is out of contract at the end of the season. 

The 32-year-old is in good enough form to play on but said he would decide on his future once the season was over.

"It's not even worth talking about until we get past the next couple of weeks," Lonergan said. 

"That's where my focus is at and I'll sit down with the club at the end of that period and discuss where we go from there." 

Geelong CEO Brian Cook joined Lonergan, Josh Caddy and Mitch Duncan at Simonds Stadium on Wednesday to announce a partnership with Barwon Child Youth and Family. 

Cook said winning the Grand Final this season would produce a financial windfall for the club. 

"If we actually win the Grand Final we'll probably make about $400,000 extra this year and that will probably be the same next year," Cook said. 

"Every other scenario, we lose. First week, second week, third week, fourth week, if you lose we actually lose dollars. 

"The only way we can make a profit in the finals is to win it all."