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.
Gareth Bale says he'll have to "see what's best for myself" if Spurs don't reach the Champions League.
A run of one win in nine Barclays Premier League outings has seen Spurs slip from title challengers to fifth place, outside the Champions League berths and facing the prospect of a second season of Europa League football next term.
Bale hopes Tottenham can produce a strong finish to the campaign and claim a top-four berth that would bring qualification to European football's top table, providing London rivals Chelsea do not win their Champions League final against Bayern Munich on May 19.
Yet should Spurs fall short, the 22-year-old Wales winger has warned that his ambition to play at the highest level could see him reassess his future.
"I had a taste of it last season and I enjoyed it thoroughly," said Bale of the Champions League in an interview with the BBC's Football Focus.
"I think everybody always wants to test themselves against the best players in the world.
"We have to wait and see what happens. Obviously if we don't [qualify for Champions League], we'll have to sit down and discuss and see what's best for myself."
Bale, who is under contract at White Hart Lane until 2015, played down reports linking him with Barcelona, however.
"Obviously it's flattering but at the end of the day I'm still a Tottenham player and I need to keep performing week in week out for not just myself but for the team," he said.