By the Numbers: Bucking bad luck
You can find more from Michael Salfino at NESN
Here is the first of two pieces looking at first-half stats that we think best isolate luck (both good and bad) so we can get a bead on which pitchers and hitters are most likely to regress and progress for the balance of the year.
For hitters, we look at outliers (relative to personal history and league averages) in batting average on balls in play (BABIP), average with runners in scoring position (BARISP) and percentage of fly balls that become home runs (HR/FB).
We judge pitchers by Fielding Independent ERA (minus actual ERA), HR/FB rates and defensive efficiency rating (DER, percentage of balls in play that become outs). To get the best read on DER outliers, we factor in a pitcher’s rate of line drives allowed (relative to league average). Remember, about 75 percent of line drives are hits.
We’re going to look at the unlucky players first. These are players our model says should pfare significantly better in the second half as their performance in these key metrics gets closer to their individual and/or league averages. Thus, we do away with the standard “Buy, Sell, Hold” format. All of the below are “Buys.”
Russell Martin(notes), C. Dodgers: He’s had about average power in his past (about 10 percent of his fly balls have been homers). He now sits at 3.1 percent. Expecting six or seven jacks the rest of the year makes sense.
Also note that Rollins (5.3 percent) and Wells (6.1 percent) are both well below recent rates, though Rollins regressed badly last year (6.6 percent), too.
FIP ERA minus ERA
Joba Chamberlain(notes), P, Yankees: His rate was 5.2 percent, 6.3 and now 15.1 this year. Lots of hitters counts due to poor control, I know. But maybe that corrects, too. Some I respect thought he’d be among the most valuable starting pitchers. And here he sits in July for the taking.
Chris Volstad(notes), P, Marlins: Last year, his rate was 4.7 percent. This year 17.7 percent. Split the difference and the ERA sinks to about 3.50. Note also his K and walk rates are improved relative to 2008.
Kevin Slowey(notes), P, Twins: His line-drive rate is about average and thus so should be his DER. Remember, DER ignores homers, which are not balls in play. So his DER should be .700, not .644. That results in a huge difference in hits allowed.
Jon Lester(notes), P, Red Sox: His line-drive rate is way below average (16.7 percent) and yet his DER is a putrid .667. Given the line-drive rate, it should be about .715 or so. And all the strikeouts are sure outs. So he can be immensely valuable in the second half.
Pavano also makes the list with his average line-drive rate (19.5 percent) not translating as it should to an average DER. His is .662. Note that in many ways, though, this list overlaps the FIP ERA list. So don’t give Pavano full double unlucky credit.
Michael Salfino’s work has appeared in USA Today’s Sports Weekly, RotoWire, dozens of newspapers nationwide and most recently throughout Comcast SportsNet, including SNY.tv, for which he also analyzes the Mets and Yankees. He’s been writing “Baseball by the Numbers” weekly since 2005.