Ironic how he joins Boston, where half the players were on the juice [like the Yankees, and yes, this is an assumption], and when he's just about to lose his job, goes on a tear that lasts for years. Then he cleans up, realizes he'd be a pariah in baseball due to his drug use, and he falls back to what he really was...a below-average hitter with no defensive skills.
This isn't a fall-off..this is a drop off the cliff. Declining skills without the help of steroids, and he's out of baseball in a year.