Atletico Madrid are hopeful of sealing a deal for Costa within the next fortnight but as of Wednesday, he remained in his hometown of Lagarto.
“They are better off without him,” Keane said on ITV. “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 balloon. Get rid of him. Have players at your club that want to be there.”
Questioned by fellow pundit, Lee Dixon, whether he indeed meant ‘balloon’, Keane reiterated: “A balloon, yeah.”