He had a rough patch in his carreer, some bad injuries etc. Great season at Besiktas last year, league top scorer. His showing at the EURO 2016 looked like he's back to his old self. Scores by the bucketload when in top form, easily good enough for United, at least as a backup striker. Fiorentina is willing to let him go for 7 Mio Euro. Will he stay injury-free, though?
For 7m he would make a decent rotation/bench striker if Wilson is off.