Astros: Brad Peacock takes flight

Thanks to a slew of injuries, the Astros decided to give Brad Peacock one more chance in the starting rotation.

A peacock is a member of the Phasianidae family, and as we all know, peacocks are not known for its flying prowess. Limited to short spurts, these avian creatures do not usually gain much distance once airborne. Contrary to popular belief, Brad Peacock is not a literal peacock. But the Astros are still finding out if he can overcome his short spurts in the past and help the team soar to unprecedented heights.

If you were to ask the average fan, most would’ve criticize the inclusion of Peacock on the active roster back in April. After all, this is a pitcher who posted a 4.86 ERA and 4.98 FIP from 2013-16 when he was on the Astros 25-man roster. And they wouldn’t be wrong, either. I mean, those aren’t the most endearing of numbers for a major league pitcher.

But the Astros saw something in Peacock towards the end of the 2016 season when he posted a 3.69 ERA in 31.2 innings. Fast forward to June 6th, 2017, and the Astros look like geniuses. And Peacock looks like a dependable big league pitcher, regardless of his role in the rotation or bullpen.

Where has Peacock’s improvement derived from?

One key to Peacock’s success this season could be his slider usage. In fact, he has generated more whiffs (43) on his slider than his four-seam fastball (16) per Baseball Savant. The crazy part is that Peacock’s slider has an average velocity of 79.77 MPH if you subscribe to Statcast’s velocity readings.

Peacock has thrown his slider 182 times this season. Last season, he threw it 186 times, yet the pitch has generated 23 more whiffs. After all, his 13.5 SO9 is much better than his 8.0 SO9 despite the similar amount of innings pitched in 2016 and 2017 (31.2 vs. 31.1).

Another interesting point is that Peacock allowed five home runs off of his slider in 2016. This year? Zero home runs have come via his slider.

Then there is the diversification of Peacock’s pitches.

For example, Peacock threw just four pitches per the Baseball Savant classification breakdown: a four-seam fastball, a slider, a knuckle-curve, and a changeup. This season, the classification lists are about the same except for the addition of a two-seam fastball. But that’s not the interesting part. It is how many times Peacock has thrown each of his pitches that will catch your attention.

2017 vs. 2016 Pitch Usage

Slider: 182 vs. 186

Four-seam fastball: 165 vs. 259

Two-seam fastball: 93 vs. 0

Knuckle-curve: 36 vs. 44

Changeup: 36 vs. 3

As you can tell, Peacock’s usage of his four-seam fastball has gone way down. His slider usage remains roughly the same compared to the amount of pitches he thrown between 2016 (492) to 2017 (512). It is the increase usage of his knuckle-curve and changeup that catches the eye along with the inclusion of a two-seam fastball.

Thus far, all of Peacock’s pitches have been reliable in 2017. The only pitch in which he has allowed a batting average higher than .200 against has been his changeup. It also happens to be the only pitch that has allowed his only home run. He has also yet to allow a single hit off of his knuckle-curve in 36 opportunities. And his top three pitches in terms of usage, the four-seam fastball, slider, and two-seam fastball, currently have produced batting averages lower than .164. The changes in usage and how he uses his pitches have definitely shown in the exit velocity readings.

Keep in the mind that Peacock’s pitch usage may change the longer he remains in the starting rotation. Remember that some of his pitches may be more effective as reliever than as a starter, but we will need more data before making a final conclusion.

Another aspect of Peacock’s game to monitor is his pitch velocity, which has been recorded slightly higher in his relief appearances than games he starts. You can find this data at Brooks Baseball.

Four-Seam Fastball/Slider Velocity, 2016-2017 (Regular Season, By Month)

8/16: 92.73/81.38 MPH

9/16: 92.88/80.55 MPH

4/17: 93.77/80.41 MPH

5/17: 93.28/81.49 MPH

6/17: 92.14/80.92 MPH

It is obvious that a pitcher’s stuff would show higher velocities when used out of the bullpen than the starting rotation. The question is whether Peacock will continue to provide the results that he has thus far in the starting rotation. But it is hard to argue against his recent success in both roles.

Jake Kaplan of the Houston Chronicle had a recent story about Peacock abandoning his wind up motion. Essentially, the 29-year old is pitching only out of the stretch now. So, that’s worth keeping an eye on going forward.

Next: Three numbers behind the Astros eleventh win a row

The Astros pitching staff has its fair share of questions going forward despite an eleven-game winning streak. However, if Peacock continues to pitch at or near his current effectiveness level, then there is one more weapon for manager A.J. Hinch to use in either the starting rotation or bullpen. Watch out, this Peacock may be starting to soar and that should the scare the rest of baseball.

**Statistics and pitch information courtesy of Baseball Reference, Baseball Savant, and Brooks Baseball**