Where’s Werth’s Power?

Jayson Werth stayed healthy and blossomed into one of the game’s best players in Philadelphia, topping five Wins Above Replacement each season from 2008-2010 while providing patience, power and speed. But no free agent signing generated more debate this past offseason than Washington’s seven-year, $126 million pact with the 32-year-old outfielder.

The controversy surrounding Werth’s deal had to do with its length — few doubted that he would rake at the beginning of his contract, but would he be worth over $20 million per year by the time Stephen Strasburg resumed racking up Ks and Bryce Harper began droppin’ bombs and blowin’ kisses in the majors?

We’re still years away from finding out the answer to that question. But there’s a more immediate concern for owners who dropped an early pick on Werth: he’s not hitting right now. Werth has a .224/.329/.391 line in 2011. Granted, Nationals Park isn’t especially friendly to right-handed hitters, decreasing offense by about three percent compared to a neutral stadium. But Werth’s production falls well short of his pre-season .263/.360/.475 ZiPS projection. Why is Werth stumbling in D.C.? Let’s take a look.

One of the biggest reasons that Werth is falling short of expectations is a decrease in his power numbers. ZiPS projected him for an Isolated Power of .212, but his ISO so far sits at .167. On a related note, Werth’s ground ball rate has increased significantly this season. During his big league career, he has hit a grounder about 38 percent of the time. This year, he’s hitting grounders a little more than 45 percent of the time. Here’s his ground ball rate by pitch type in 2010 and 2011, compared to the MLB average:

Werth’s hitting many more fastballs, curveballs and changeups into the grass. That hasn’t had a negative effect on his performance against changeups, according to his Pitch Type Values, but it seemingly has hurt him against fastballs and curves.

While Werth’s uptick in ground balls is troubling, he has had some pretty lousy luck on balls put in play. His BABIP is .262, over 60 points below his career average. Werth is popping the ball up more often this season, but even so, his expected BABIP is around .320. ZiPS isn’t as optimistic, but still gives him a rest-of-season BABIP close to .300. In other words, Werth’s average won’t likely continue to languish in the low-.200s.

At the very least, Werth owners should expect his average to rebound more toward the .250+ range during this season’s second half. It’s too early to make much of his power decline. But the safe bet might be to split the difference between his current power output and his pre-season projection, expecting an ISO around .200.

Werth is hardly done, though he does need to stop chopping the ball into the ground so often if he’s going to regain elite status. Current owners should sit tight and wait for a rebound, while others should explore a trade if Werth can be had for 60 or 70 cents on the dollar.

Ground ball by pitch type data from Joe Lefkowitz’s Pitch F/X site; MLB averages from The Hardball Times‘ Harry Pavlidis.