Cardiff will allow long-serving Kevin McNaughton to leave this summer along with Danny Gabbidon and Nicky Maynard.
Highly-rated Atletico Madrid midfielder Saul Niguez has signed a new five-year contract.
Joe Ledley admits the prospect of another Champions League run will be at the forefront of his mind when it comes to contract extension talks with Celtic in the summer.
The 26-year-old Hoops midfielder, signed from hometown club Cardiff in 2010, has another year left on his deal but has been linked with a move back to the Bluebirds, who will be playing in the Barclays Premier League next season.
However, Ledley is keen to replicate this season's Champions League exploits which saw Neil Lennon's side reach the last-16 of the competition before exiting to Italian giants Juventus.
The Wales international said: "I don't know anything (about Cardiff). I haven't spoken to my agent, all I can do is concentrate on my football and hopefully stay at Celtic.
"In pre-season I can sit down with my agent and with the people at Celtic and hopefully come to an agreement.
"The majority of players would want to play in the Premier League but you have the opportunity to play in the Champions League at Celtic, the best competition in the world, and the majority of players would want that.
"Champions League games at Celtic Park - it is the best atmosphere I have ever witnessed.
"We had a taste of it this season so hopefully we can do exactly the same next season and prove to everyone again how good a team we are.
"It is going to be a long season, we are back in early for pre-season for the qualifiers again and it is going to be as difficult as last season.
"But hopefully we can do what we did this season and make the Champions League, it would be a fantastic achievement if we could do that."
Ledley also believes the winning mentality he has developed in his time with the SPL champions, who are looking for the domestic double when they take on Hibernian in the William Hill Scottish Cup final at Hampden later in the month, would make leaving Parkhead difficult.
"When you sign for Celtic you have got to win," he said.
"It would be difficult now to go somewhere else and say 'we'll take a point here' or 'make sure we don't lose by two'.
"It is totally different. You have this winning mentality and that's what you want to do as a player, you want to win every game."
Ledley is back in Glasgow after a week's rest in Dubai, refreshed and ready to get Celtic back on track following last week's 3-1 defeat at Motherwell.
"With the amount of games we play it was good to have a rest but I look forward to the rest of the season," he said.
"I watched some highlights of last week's game, I know some of the boys weren't happy with some of the performance but it was one of those games.
"Motherwell have been fantastic this season but hopefully we can bounce back against Ross County. That is going to be a very difficult game.
"They beat us last time we were there so hopefully we can play better than we did then."