The Reality of Jorge De La Rosa by Eno Sarris May 18, 2009 A question in the mailbag from L. S. this week ended simply: Is Jorge De La Rosa for real? His 2.99 FIP seems to suggest that his good start is for real, but ZiPS has him putting up a 4.71 ERA for the rest of the season. Perhaps this is a nod to his 5.32 career ERA. Many projection systems have trouble with breakout seasons, however, and there’s ample evidence that we are actually witnessing just such a step forward from a talented pitcher that could be peaking in his 27th year on the planet. For one, the ‘luck’ numbers do not point definitively towards an unsustainable start to the year. His 69.1% strand rate is close to the league average as well as his own average (67.7%). His BABIP is .298, and while that is lower than his career .325 number, it doesn’t scream luck, especially given the small sample size. Sure, this sample size also could be skewing his strikeout and walk rates, but for now they are both (9.49 K/9; 3.38 BB/9) right near the rates he put up in 130 innings of 4.06 FIP baseball last year (8.86 K/9, 4.29 BB/9). If the trend holds steady, the rates also show a natural progression that is encouraging. His strikeout rate has improved for three straight years, and his walk rate is at its lowest in his career. That’s good work if it proves to be true. The only ‘luck’ worries come from his fly ball numbers. He’s sporting a 26.8% infield fly rate, and as those balls turn into long fly balls, his 4.9% HR/FB number should rise up to his 10.3% rate. The surprising thing is that with such a great HR/9 number (0.42), De La Rosa can actually continue to be productive – even if he doubles his home runs per nine as his career number suggest he will. Why all the optimism? What’s changed? In short, this young Rockies pitcher has changed his entire approach to pitching over the past years. Take a look at his pitch selection, and the difference between now and his first extended burn in 2007 is stark. When he came into the league, De La Rosa was throwing his 92-93 MPH fastball 62.3% of the time, and his 83 MPH slider 1.7% of the time. This year, he’s throwing those two pitches 56.1% and 23.3% of the time, respectively. He’s also cut his use of his 75 MPH curveball in half, from 13.1% to 6.5% this year. A peek at his most recent pitch F/X game graph gives us some insight into this changed usage pattern. Take a look at his release points. Jorge De La Rosa Release Points on 5/15/09 Despite a consistent release point for most of his pitches, De La Rosa lets his curve ball go at a distinctly higher point than his other pitches. This could lead to batters identifying the pitch early and laying off. Now take a look at the movement of his pitches. Jorge De La Rosa Pitch Movement on 5/15/09 Given that the curve ball has the most horizontal and vertical movement of any of his pitches, it also follows that the curve ends up being called a ball many times, especially if batters are noticing the different release point and watching it into the catcher’s glove. It also makes sense that his most effective three pitches might be the three that release at the same spot and break as differently as his fastball, changeup and slider do. Could it be that his reduced walk rate can be attributed to his reduced use of the curveball? Correlation is of course not causation, so it’s hard to say without knowing the strike percentage of each of his pitches. But De La Rosa is a changed pitcher – that much seems clear. And that counts as a good thing.