He's joining Milan permanently but he's off to Atletico for a loan deal, probably for two years. Milan seem to be forking money out to pack him off on loan!
I feel for him as I was a fan when he was at Atletico but he did do OK at Chelsea at times, more in Europe but it seemed his mind had completely gone from a striker's POV. He seemed comfortable hogging the wings and working hard rather than getting in the box to try and score.