Warning: These numbers need to be taken with a grain of salt. Much like batted ball data, two different sources can classify a pitch as two different pitches if the movement of the two pitches are similar (like a curveball and a slider). However, I thought this would be interesting enough to see what Rick Porcello’s 2012 season would look like without his slider since Pitch f/x gives us enough information where we can subtract out the numbers.
As has been reported, Rick Porcello has scrapped his slider and is throwing his curveball more often. The results during Spring Training have been great. In 24 innings, Porcello has a 3.00 ERA, 0.75 WHIP, 21 strikeouts and zero walks. Has the change in pitches really made him this good? Maybe.
Pitch f/x gives pitching values for each pitch type a pitcher has. Average is 0, positive results are above-average and negative results are below average. Here are the numbers for Porcello in 2012:
4-Seam Fastball | -4.1 Runs |
2-Seam Fastball | 1.8 Runs |
Slider | -17.3 Runs |
Curveball | 0.6 Runs |
Changeup | 0.3 Runs |
How bad was his slider? According to Pitch f/x, Porcello’s 2012 slider was the worst rated slider by 7.7 runs (Clayton Richard’s slider was rated at -9.6 runs). We can even go deeper in the stats to see individual batting lines for each pitch:
PA | BB | K | HR | AVG | OBP | SLG | |
2-Seam Fastball | 396 | 26 | 44 | 8 | 0.310 | 0.360 | 0.426 |
4-Seam Fastball | 155 | 6 | 28 | 3 | 0.292 | 0.329 | 0.438 |
Slider | 111 | 2 | 17 | 2 | 0.394 | 0.405 | 0.615 |
Changeup | 103 | 7 | 14 | 3 | 0.240 | 0.291 | 0.406 |
Curveball | 16 | 0 | 4 | 0 | 0.250 | 0.250 | 0.313 |
Total With Slider | 781 | 41 | 107 | 16 | 0.309 | 0.349 | 0.451 |
Total Without Slider | 670 | 39 | 90 | 14 | 0.294 | 0.340 | 0.423 |
Difference | 111 | 2 | 17 | 2 | 0.015 | 0.009 | 0.029 |
Hitters hit .394/.405/.615 off of Porcello’s slider last year with a total batting line against of .309/.349/.451. By subtracting out the slider, the batting average falls 15 points, the on-base percentage falls 9 points and the slugging percentage falls 29 points. His strikeout rate remains virtually unchanged, which kind of surprises me (13.7% with the slider, 13.4% without).
Giving a quick calculation of innings pitched, (H-AB+GIDP)/3, here are estimated innings pitched per pitch type as well as their FIP:
IP | FIP | |
2-Seam Fastball | 89 2/3 | 4.24 |
4-Seam Fastball | 36 1/3 | 3.37 |
Slider | 22 2/3 | 3.01 |
Changeup | 24 1/3 | 4.41 |
Curveball | 4 1/3 | 1.25 |
Total With Slider | *176 1/3 | 3.91 |
Total Without Slider | 153 2/3 | 4.04 |
Difference | 22 2/3 | -0.13 |
*The innings pitched doesn’t total his real innings pitched. I think this is because of errors (8) and caught stealing (5). (8-5)/3 = 1 inning, exactly how much that I’m off by. I don’t think this is a problem, since we can assume that these events would still happen regardless of the type of pitch he threw.
It’s interesting that his slider didn’t result in a high FIP. FIP probably isn't helpful here, given the small sample size and the fact it only factors in home runs, walks, hit by pitches and strikeouts. Porcello wasn't horrible in those stats with his slider.
Going further down, they even give individual batted ball percentages for each pitch:
LD | GB | FB | |
2-Seam Fastball | 21.5% | 60.4% | 18.0% |
4-Seam Fastball | 19.1% | 50.4% | 30.4% |
Slider | 27.5% | 46.2% | 26.4% |
Changeup | 18.3% | 43.9% | 37.8% |
Curveball | 33.3% | 41.7% | 25.0% |
In order to subtract the slider from this, we’ll need the raw numbers…which they don’t give. We can calculate batted balls by taking AB+SF-K-Bunts. They give at bats, sacrifice flies and strikeouts, but they don’t give bunts. There are 9 bunts that need to be subtracted out, but pitch f/x doesn’t show which pitch type was for each bunt…but MLB Gameday does. According to MLB Gameday, there were 5 bunts on 2-seam fastballs, 3 on 4-seam fastballs and 1 on the slider. Using 2 different sources for this information does make it lack credibility, but at least we can get a good idea. Now we can take the batted balls and multiply it by the percentage to get the raw numbers:
Batted Ball | LD | GB | FB | |
2-Seam Fastball | 316 | 68 | 191 | 57 |
4-Seam Fastball | 115 | 22 | 58 | 35 |
Slider | 91 | 25 | 42 | 24 |
Changeup | 82 | 15 | 36 | 31 |
Curveball | 12 | 4 | 5 | 3 |
Total With Slider | 616 | 134 | 332 | 150 |
Total Without Slider | 525 | 109 | 290 | 126 |
And then divide it back out without the slider stats:
Batted Ball | LD | GB | FB | BABIP | |
With Slider | 616 | 21.8% | 53.9% | 24.4% | 0.343 |
Without Slider | 525 | 20.8% | 55.2% | 24.0% | 0.324 |
Difference | 91 | 1.0% | -1.3% | 0.4% | 0.019 |
It’s a small difference, but there’s a full percentage point difference of line drive to ground balls in the positive direction. And his BABIP falls almost 20 points. Sure, defense was a big reason why his BABIP was high, but so was his ineffective slider.
Of course, he isn’t just eliminating his slider. He’s replacing it with more curveballs. If it’s an above average curveball, the changes will be even more prominent.