Defender Ricardo Carvalho has criticised Chelsea for their treatment of former manager Avram Grant and accused the club of a lack of stability.
The Portugal international centre-half will be joined at Stamford Bridge by current national team boss Luiz Felipe Scolari next season.
However, Carvalho will be working under his third manager in four years with the club and doesn't believe that their constant chopping and changing is conducive to success.
The 30-year-old was brought to Chelsea from FC Porto by Jose Mourinho in 2004 and was coached by Grant last season before his departure at the end of the recently completed season.
"Avram did a great job, but they still decided to sack him. Yet after Jose Mourinho left, he picked up the team and got good results," Carvalho told the Sunday Times.
"It was very cruel. He did a great job and he could have carried on, but they decided to let him go. It was very ruthless.
"The new manager will be my third in a year and in football you need stability if you want to be successful."
Meanwhile, Carvalho has played down suggestions that he could follow Mourinho to new club Internazionale.
"There has been a lot of talk about the new manager and players coming and going. I know there are stories about me, too and in football you never know what can happen," he added.
"But I have a contract at Chelsea and I have not spoken to Jose Mourinho about Inter, or to my agent about a move."