TOM Rockliff says he is worried more players could follow Jack Redden's lead and leave the Brisbane Lions.

Redden spoke to coach Justin Leppitsch on Tuesday and formally requested to be traded with one year remaining on his contract.

Rockliff has been best mates with Redden since the pair joined the club before the 2009 season and said he had done everything possible to change the South Australian's mind.

But the Lions skipper admitted he was concerned others may follow suit.

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"That's the concern at the moment. When one goes, you're always worried," Rockliff said on Wednesday morning.

"And when you get to this time of the season there's always the 'is he going to go, is he not going to go' and there's speculation about a lot of players.

"We don't know until they come and tell us.

"Majority speaking, I think most of the group's happy."

Rockliff said he spent all of Monday afternoon and evening trying to convince Redden to stay, but without luck.

Free agent Matthew Leuenberger is all but certain to leave the club, while Stefan Martin and Dayne Zorko were previously named as looking elsewhere, but now seem to have been appeased.

This is all after the club told former skipper Jed Adcock he would not be required in 2016.

In what he admitted was the most difficult season of his seven-year career, Rockliff said it was important the Lions kept some experience on their list.

He said losing Redden would be a major loss if he didn't have a change of heart.

"I don't think there's anything I can do to change his mind," Rockliff said.

"His issues are with other things within the footy club.

"Reddo is my best mate, so it does make it hard when he says that.

"We have to have a look at the way we do things around the footy club and if he's upset, then we need to improve in some areas of our footy to make sure we can retain them and keep players happy."

Just two years ago the Lions lost five first-round draft picks, who all wanted out and returned to their home states.

Jared Polec, Elliot Yeo, Billy Longer, Sam Docherty and Patrick Karnezis all left during the 2013 trade period, gutting the club of much of its young talent.

Rockliff said it felt different this time, as the young players felt content, and the grumblings were coming from the older players.