Despite the fact Caballero will also feature as a reserve option at his new club, just as he did for the vast majority of his stay at the Etihad Stadium, one could easily say he's pulled off an impressive late upgrade in his career.
"I am looking forward to meeting the guys and helping the club achieve more success in the coming season".
'Caballero arrives having been out of contract at Manchester City.
Caballero, as reported some time back, signs a one-year deal with the Blues as he takes Asmir Begović's place on the bench behind first-choice Thibaut Courtois.
What we know about the Bronx Hospital gunman so far
They say Bello then shot himself, and staggered, bleeding, into a hallway where he collapsed and died with the rifle at his side. Police went floor by floor searching for the shooter while the hospital had been surrounded by emergency response vehicles.
The club's technical director Michael Emenalo added: "We are very happy to have Willy on board". A master at saving penalties, the 6-foot-1 keeper stopped Colombian striker Falcao from the spot in the first-leg match in the Round-of-16 against AS Monaco.
Keown, son of former Arsenal defender Martin, is manager Alan Archibald's third summer signing, following the arrivals of Blair Spittal and Jamie Sneddon.
'We have three experienced goalkeepers and we look forward to welcoming him to the club when the squad returns to pre-season training'.
Prior to Caballero's time in the Premier League, he spent four seasons with Malaga in La Liga.