'The guy is a bit of a balloon' - Roy Keane with a damning verdict on one of the Premier League's biggest stars
Republic of Ireland assistant manager Keane had a reputation for being a difficult character to manage during his playing days, with his 'passionate' personality inspiring numerous high profile clashes with players, manager and match officials.
Yet when he was asked to sum up the antic of Chelsea striker Costa in his role as an ITV pundit, the Irishman did not hold back as he condemned the Spain forward after his actions in recent weeks.
Costa has not returned to training at Chelsea this season after being informed he would not have a role in the plans of Blues boss Antonio Conte tis season, with Keane unimpressed by his extended holiday back home in his native Brazil.
"They are better off without him," declared Keane. "The guy is obviously big trouble.
"I know he has done well for them, but he looks to me to be a bit of a baloon. Get rid of him. Have players at your club that want to be there."
Despite their troubles off-loading Costa amid protracted negotiations over a move back to his former club Atletico Madrid, Keane has predicted Chelsea could be dark horses to challenge in the Champions League this season.
"I don't know why Chelsea are under the radar," Keane added as he summed up their trophy hopes this season.
"You look at what the manager achieved last year, the options he has and they have some fantastic players who are used to winning big games. So they are a threat in this competition, without a doubt."