I recall Gurriel had off season wrist surgery. It seems very likely that was directly behind the power slump last season. His batted ball metrics were all surprisingly close to his career norms but his barrel rate in particular cratered, and his HR/FB% did the same. He's not hitting the ball much harder on average this season, and he's not hitting more flyballs either, however he is pulling the ball a bit more so perhaps that's helped more balls leave the park.