Possibly because he swings and misses almost twice as often as the average MLB hitter. It could also be that he strikes out in about 30% of his at-bats. It could also be that his HR/FB rate is the highest in the majors, higher than those of Jim Thome, Joey Votto, and David Ortiz. First, those swing and miss rates don't bode well for him in the future as a guy who can make consistent contact. Second, I'm inclined to think that his HR/FB rate is unsustainable and that it will fall.