Tuesday, August 11, 2009

What Core Numbers Don’t Reveal

On the surface, Ricky Nolasco’s statistics (8-7, 4.86 ERA) make his season look far worse than his strong 2008 campaign (15-8, 3.52). Believe it or not, he has actually pitched better this year than last.

Nolasco has struck out 23 percent of the batters he’s faced in 2009, compared to 20.9 a year ago. In fact, he has a chance to become the first Marlins ERA qualifier to strike out over a batter per inning. He’s also allowed home runs less often than during 2008. Although his rate of unintentional walks has risen, Nolasco has fared better in the statistics where he has the most control.

The biggest reason for his higher ERA this season is poor luck. The Marlins righthander has allowed a .337 batting average on balls in play. Without getting into the detailed explanation, this means that the Florida fielders have converted an extremely low percentage of batted balls into outs with Nolasco on the mound. He also has the NL’s lowest left on base percentage (63.3), another example of poor luck. As the season progresses, these trends should become less extreme and Nolasco’s ERA will therefore improve.

A pitcher's statistics get impacted by the quality of hitters they face as well. The batters who have hit against Nolasco owned a higher combined OPS (.746) than those faced by all but one other NL pitcher.

When you take an in-depth look at his numbers, Nolasco has improved from last season. Especially in time frames less than a full season, core numbers can prove misleading.

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