This season, Astros' fans thoughts have begun to shift to next year, and the future after that. Two important pieces for the Astros puzzle are young starting pitchers Bud Norris and Felipe Paulino. Both are hard throwers, and have shown flashes of domination in some games. In this article, I will take a quick look at Paulino's HRs this year. Paulino's 19 HRs allowed has been one of his biggest weaknesses.
Although Paulino's ERA and FIP (fielding independent pitching) are both significantly higher this year than what Norris has posted, that picture changes if we look at x-FIP, which is FIP adjusted for normalized HRs (i.e., league average HRs per flyball).
The theory behind x-FIP is that pitchers have limited control over HR rates per flyball. Certainly, pitchers can control their HR/game rate by throwing more groundball pitches. But HR/flyball rates significantly higher than league average may be more affected by luck, and should be viewed more skeptically. Paulino's 18.7% rate is significantly higher than the typical rate of 11% - 12% per flyball. Paulino's x-FIP would represent an above average starting pitcher. Notice I said that a high HR/fly rate should be viewed with skepticism, but I didn't say it fully absolves the pitcher's performance. Presumably, a pitcher's command or stuff may be so bad, for example, that it could lead batters to just plain hit the ball harder and farther.
Looking at hit tracker, we see some support for the notion that Paulino's high HR/fly rate may reflect some randomness. In terms of HR distance, Paulino has 5 "just enoughs" (HR barely cleared wall) and 2 "lucky HRs" (wouldn't be a HR under normal conditions). Without those HRs, the remaining HRs would put Paulino very close to the typical rate of 11 - 12%, and the 4.07 FIP shown above. The average standard distance of HRs allowed by Paulino (393.7 ft.) is around the median for pitchers who allowed 18 or more HRs.
Another important element of Paulino's vulnerability to the HR this year is his difficulty with lefthanded batters. Lefthanded batters are 2.5 times more likely to hit a HR off Paulino than righthanded batters (2.8 HRs/PA for RHB vs. 7.1 HRs/PA for LHB). Paulino's problems with LHB extended beyond HRs---LHBs had a .409 OBP compared to .340 for RHBs.
So, here are some quick thoughts about potential improvement for Paulino next year. First, Paulino may well see a regression to mean in his HR rate, which will significantly improve his pitching results next year. Second, Paulino should work on improving his ability to get LHBs out. Perhaps he needs to work on another pitch which will be effective gainst lefthanders. Third, an improvement in Paulino's groundball rate would also decrease his HR vulnerability. Jim Deshaies has suggested that Paulino should work on an effective sinker, which would have the effect of improving the groundball rate. The downside to throwing more 2 seam fastballs is that Paulino's average velocity likely would decline, as well as potentially decreasing his strikeout rate. I wouldn't say that Paulino should change his basic style and become a "pitch to contact" pitcher, but careful use of a sinking fastball, particularly to LHBs, wouldn't hurt.
In the end, though, I remain optimistic about Paulino's future.