David Ortiz’s Power Decline

Yesterday I looked at David Ortiz’s decline in plate discipline values. Today I am going to turn to his power numbers. Because of Ortiz’s inclusion on the leaked 2003 list of players who tested positive for performance-enhancing substances, any discussion of his power is going to turn to speculation based on that, but I am not particularly interested in covering that angle and prefer to focus on his numbers.

Ortiz’s power decline has come in a very particular manner. Look at his ISO to each field over the years. His peak years were 2003 to 2007 before his decline began in 2008.

            ISO
       left  center  right
2003   .327   .310   .429
2004   .260   .380   .449
2005   .223   .345   .493
2006   .260   .460   .533
2007   .280   .272   .444
2008   .256   .196   .383
2009   .290   .331   .276

In his peak Ortiz showed a typical left-handed power-hitter split with his biggest power coming to right field. In the past two years, interestingly, his power to left and center held steady while to right it has fallen off. His loss of power has been almost exclusively a decrease in power of pulled balls in play. Showing it graphically (with the number the fraction of balls in the air to each region and the shading the slugging on those):

The fraction of those to deep right and the slugging on those balls in play has fallen off in the past two years, while the fraction of balls in play to the infield and just beyond has risen.

It is interesting that Ortiz has lost power to right while he has tried to swing more at inside pitches, which he would typically pull. It could be that as Ortiz has lost some power to right he has tried to compensate by swinging at more inside pitches in an attempt to get the big pull power on them.

One encouraging sign, as a commenter to yesterday’s post pointed out, is that after a horrid April and May, Ortiz had a much better June through September.

Generally, though, I find it interesting that his power to center and left has been largely unaffected and wonder how that compares to other aging sluggers.