Gonzalez has moved from San Diego to Boston and immediately become the class of the position within the eastern division.
In spite of playing half of his games in San Diego’s Petco Park, and batting in the middle of a weak offensive lineup, he has hit 30+ HR and driven in 99+ runs in four consecutive years. Entering last season, his notable weakness (beyond his one career stolen base) was his struggles against left-handed pitching. But last year he was a far more effective hitter against southpaws (.337) than against righties (.278), although he continued to exhibit far more power against right-handers (23 HR in 392 AB, vs 8 HR in 199 AB against lefties).
His batting average was enhanced by a 38% hit percentage against southpaws. It is highly unlikely he will maintain such success with the Red Sox, especially when considering the quality of southpaws he will face in the eastern division.
Still, Fenway Park should play to his strengths and enhance his statistics (see the analysis I conducted on his balls-in-play from last season here). He has had an excellent walk rate (13-14%) and contact rate (80%+) over the last couple of years, and there is no reason to believe those numbers will regress playing in Boston in his new lineup.
For fantasy owners: Gonzalez is currently going eighth in the mock drafts.
I expect he will benefit from playing at Fenway Park, but that some of those gains will be masked by a regression against lefties. He’ll certainly benefit from hitting in the middle of the Red Sox lineup, which will provide increased RBI-opportunities and runs scored. I think you can expect a .300+ BA, 38+ HR, 130+ RBI and 110+ R.