Alvarez' lifetime ERA in Toronto's Rogers Center (where he toiled from 2011-12) is 4.68, while his ERA at Marlins Park in Miami (eleven GS beginning last year) is now at 3.47.
His CG today was a two-hitter against the Seattle Mariners. Alvarez was particularly efficient, as is increasingly the case in CGs during our pitch count-conscious age: he threw only 90 pitches.
It's clear from his splits data that he's going to have to find a way to get left-handed batters out if he's going to be a successful starter in the big leagues.