Considering that a decrease in bat speed might be at issue, I decided to look at Jeter’s contact percentage last season to see if anything changed from previous years.
How do Jeter's contact numbers up in the zone compare to his 2009 numbers?
Across the board, Jeter’s contact rate was down 5% in 2010. Against fastballs in his power zone, it was down nearly 8%. And against right handed fastballs in that zone, his contact rate was down more than 10% from 2009 (79.4% to 68.7%). Again, I don't know if this is due to a drop in bat speed, or if his bat speed saw any decline at all from 2009 to 2010. However, Jeter was swinging and missing at a greater rate in an area where he gets most of his big hits.
Given the drastic drop in power, Jeter’s 2010 was likely not all a result of decline due to age. He could simply have had an off year, with his problems only partly a result of age related factors. He had a terrible season against RHP which contributed greatly to his overall power outage. However, his numbers do look similar in many respects to his 2008 season numbers, with 2009 looking like the outlier.
I’m really not sure what to expect out of Jeter in 2011. He probably won’t be as bad as he was in 2010. But unless he can correct his troubles against RHP, I doubt we’ll see him approach anything close to his 2009 production.