That’s the verdict of Roy Keane, who’s branded the wantaway Spain international a "balloon".
Costa revealed in June that Antonio Conte told him by text that he’s free to leave Stamford Bridge.
But Chelsea failed to thrash out a deal for the 28-year-old to return to Atletico Madrid this summer.
The La Liga giants have been linked with a move to sign Costa despite the transfer window being closed.
Chelsea’s bid to offload him has been hampered though by the fact he’s spent the past few months in Brazil and refused to return to London.
Keane offered his take on Costa during a discussion with Lee Dixon on ITV’s Champions League coverage.
And it’s safe to say the Manchester United legend is not impressed by the way the striker’s behaved.