2020 Negative Regression Candidate: Jack Flaherty
Jack Flaherty’s 2019 campaign was a tale of two pitchers.
Before the All Star game on July 19, Flaherty was a really poor, below average starter. Flaherty started 18 games and tossed 97 innings in the first half of the season. In those 18 starts, he posted a 4.64 ERA, 4.74 FIP, 1.23 WHIP, and a 110 ERA-. He also struck out 107 batters.
ERA- is the pitcher’s version of wRC+, where 100 is average and one point above or below 100 is seen as one percentage point above or below league average. Using this information, we can conclude that Flaherty was about 10 percent worse than the league average in the first half of the season.
Then came the All Star break. I’m not sure what Flaherty ate or drank during his time off, but whatever he did — it worked.
In the second half of the season, Flaherty started 15 games and threw for 99.1 innings of work. He was nearly unhittable. Flaherty posted a 0.91 ERA, 2.22 FIP, 0.71 WHIP, punched out 124 hitters and had a 22 ERA-.
Read that again… A 22 ERA-. That means that Flaherty was 78 percent better than league average in the second half of the season. To put into perspective just how dominant Flaherty was in the second half, Gerritt Cole — the man who signed the largest contract in MLB history for a pitcher this offseason — had a 56 ERA- in 2019.
Obviously, this all left me with one big question: Why?
Why was Flaherty so much better in the second half than he was in the first half? What changed that caused such a drastic spike in performance? I decided to dig into the numbers to see what I could find.
When you glance at Flaherty’s first and second half splits, one thing really stands out: his ERA and his FIP.
In the first half, Flaherty’s ERA was 4.64 and his FIP was 4.74.
For those who don’t know, FIP is a measure of a pitcher’s performance independent of the performance of his defense. It’s essentially a measurement of what a pitcher’s ERA would look like over a stretch of time if given league-average defense.
In the second half of the season, we can see that Flaherty’s ERA (0.91) was miles better than his FIP (2.22). A 2.22 FIP is outstanding, but the contrast in FIP and ERA in the second half tells us that Flaherty likely experienced some excellent defense behind him and some lucky breaks that fell in his favor.
I was curious where some of the defenders behind Flaherty fell in terms of Outs Above Average. Sure enough, several of them fared pretty well. Paul DeJong was 5th among shortstops in OAA; Harrison Bader was 4th among center fielders; Matt Carpenter was 7th among third basemen; Kolten Wong was 2nd among second basemen; and Paul Goldschmidt was 3rd among first basemen.
The Cardinals as a team finished 4th in the majors in DRS and 3rd in UZR. Flaherty did, indeed, have an elite defense behind him.
Flaherty got hit fairly hard in the first half of the season. He allowed 101 hard hit balls (balls that are hit 95 mph or harder), which was the 75th most of the 200 pitchers that threw at least 750 pitches before the All Star break. In the second half of the season, Flaherty allowed just 44 hard hit balls, which was tied for the second fewest of the 129 pitchers that threw at least 750 pitches.
Not only did he allow significantly fewer hard hit balls, but he was experiencing some better luck on those hard hit balls. In the first half of the season, the hard hit balls Flaherty allowed had an xBA of .566, an actual BA of .560 and a .444 BABIP. In the second half, the hard hit balls he allowed had an xBA of .530, an actual BA of .409 and a .333 BABIP. He was simply finding more gloves.
Like this 110.1 mph screamer off the bat of Kyle Schwarber:
Another thing I found that I thought was interesting was an uptick in Flaherty’s fastball velocity. In the first half of the season, Flaherty’s fastball was sitting at 93.9 mph. In the second half, it went up nearly an entire mile per hour — 94.8. The last month of the season, Flaherty’s average fastball velocity was up to 95.1 mph. That’s a pretty substantial jump.
Of the 17 hardest fastballs Flaherty threw in 2019, 16 of them came after the All Star break. Like when he touched 99 mph in the eighth inning in this September game against the Cubs:
His fastball didn’t generate a higher SwStr% in the second half. In fact, it generated a lower one (10.3% as opposed to 10.9% in the first half). He did allow weaker contact in the second half, though — and that is always a good thing.
Flaherty allowed 25 barrels on 279 batted balls in the first half of the season, good for a 8.96 Brl%. In the second half, Flaherty allowed just 8 barrels on 200 batted balls — a 4 Brl%. That huge drop in Brl% is always going to lead to an increase in run prevention.
Flaherty’s late-season uptick in velocity, his generating weaker contact, the elite gloves behind him, and some lucky bounces all contributed to his stellar second half. The 0.91 ERA is by no means indicative of what is to come for Flaherty. The 2.22 FIP, on the other hand, is a much better basis to build off of when trying to predict Flaherty’s success moving forward.
If you’re expecting a 2020 Flaherty campaign (if we get one) similar to the 7–2, 0.91 ERA, 0.71 WHIP, 5.4 K:BB line that he posted in the second half of last year, you’re in for a big disappointment.
