Lessons on Werth, Hart and Fielder

Werth's power drop was predictable; the same notion applies to trade bait and impending free agents. Getty Images

In March, we speculated that Jayson Werth of the Philadelphia Phillies would suffer a power outage this season. Last year, he went deep 36 times -- besting his previous career high by 12 homers -- and this year, as August approaches, he has 14 homers. Based on the data I collect at HitTracker, there's an easy explanation for Werth's power outage, and it explains why the Brewers should sell high on Corey Hart, though his recent wrist injury might make that impossible. Allow me to explain.

HitTracker classifies each MLB home run into one of four categories, based on how far past the fence it flew:

• Inside-the-park (ITP)
• "Just Enough" (JE): cleared the fence by 10 vertical feet or less.
• "No Doubt" (ND): landed at least 50 feet past the fence.
• "Plenty" (PL): every other home run.

Of Werth's 36 HRs last season, 17 were of the "JE" type (47 percent). League-wide, the average JE percentage fluctuates around 32 or so. Over the years 2006-08, only 13 players posted a season in which they hit 30 or more homers with a JE rate of 40 percent or higher; of those 13 hitters, 11 saw their home run rate drop the next year, and collectively these 13 players hit 23 percent fewer home runs per at-bat in the following season.

Among notable players at this year's trade deadline -- and next offseason -- Werth is one of a handful of guys where JE rates paint a picture of the type of hitter a team may be getting.