Expanded Four Factors: Aaron Hill’s BABIP by Jack Moore August 11, 2010 Expanded Four Factors links: Ryan Howard Average Player Math/Reference Aaron Hill has a .199 BABIP in 406 plate appearances in 2010. That is, unsurprisingly, the worst among qualified players, coming in 11 points below Carlos Quentin‘s mark and a staggering 34 points below Carlos Pena’s .233, second worst among players with at least 400 plate appearances. Naturally, this is a huge reason why Hill’s wOBA this season is all the way down to .300, 57 points down from his breakout 2009 season and 31 points below his career average. This drop in BABIP isn’t completely unexplainable. Hill’s LD% is all the way down to 10.2% from 18.8%, and those missing line drives have all turned into fly balls. Some around the Jays have noted that Hill has had more loft to his swing, which would explain this change. Given that LDs are the most likely to fall in for hits (.722 BABIP) and FBs are the least likely (.140 BABIP), that explains a lot. That’s roughly 27 line drives turned into fly balls, or 15 fewer hits. In 296 balls in play, those 15 hits account for 50 points of BABIP. Still, that would leave Hill’s BABIP at .249, in the bottom ten of the league. That provides us with a fantastic opportunity to use our new favorite tool, Four Factors Equivalent wOBA (ffwOBA). Check the links at the top if you’re interested in the methodology. The following graph shows how Hill’s wOBA should change as his BABIP increases. The fact that Hill’s wOBA is still at .300 (estimated at .292 by the method) is encouraging. The 50 point difference in BABIP mentioned above would bring Hill’s ffwOBA up 55 points to .347 from .292. If he were to get back to .288, his mark from last year, his current peripherals would have him as a .389 wOBA player due to his high power and contact rate. Hill, especially now, certainly doesn’t profile as the kind of hitter who could post above average BABIPs. For something really extreme, if Hill’s BABIP were to reach .360, with the amount of power and contact Hill makes, the Four Factors method would estimate a .464 wOBA. That’s not likely to happen, but it’s interesting to see. ZiPS projects Hill’s BABIP at .258, and I’d expect it to come up to the .270-.280 range, as he has shown the ability to do so in the past. Either way, Aaron Hill should, as long as he can turn a few of FBs into LDs, become an above average hitter once again, and soon.