What's wrong with Prince Fielder?

Prince Fielder entered Tuesday's action ranked fifth in the American League with 81 RBIs. Since we still largely worship at the altar of RBIs, it's overshadowed the fact that Fielder is having the worst season of his career, hitting .261/.352/.432 as the night began. Among qualified batters, he ranks just 55th in OPS after ranking seventh a season ago. The RBIs are easily explained: Fielder has hit with more runners on base than hitter in the majors -- by a large margin (400, 24 more than Brandon Phillips).

Justin Havens of ESPN Stats & Info looks at Fielder's struggles this year -- especially against right-handed pitching and fastballs:

Regardless of righty or lefty, Fielder is getting beat by fastballs this season. He’s slugging only .404 (115th in the majors) against those pitches. Just two seasons ago, Fielder feasted on heaters, slugging .607 against them, 16th among all players.

It's too soon to say if the Fielder's bat is slowing down or if maybe he's just having one of those season, unlucky on a few fly balls that landed on the warning track instead of inching over the fence (he's always been more of a line-drive hitter with power than a guy who blasted towering home runs). The Tigers still lead the AL in runs per game, but imagine how good the offense would be if Cabrera and Fielder were both clicking.