Jeremy Guthrie’s Second Half Success

Throughout his career, Jeremy Guthrie has somehow found a way to overperform his peripherals. In every one of his major league seasons, his ERA was lower than his FIP, and for his career, he has an above average ERA+. Despite never having a full season with more than 6.31 strikeouts per 9 innings, Guthrie has been able to put up a respectable career due to sustaining a BABIP that is quite a bit below the league average (.278 for his career, while .300 is typically normal).

I don’t understand how he’s done it, but the fact remains: he’s done it.

Mandatory Credit: Peter G. Aiken-USA TODAY Sports

At this point, I’ve essentially stopped expecting Guthrie to regress. I expect him to put up a FIP between 4.50 and 5.00, while keeping his ERA closer to 4.00. But in the first half of the season, his peripherals were even worse than normal. Prior to the All Star break, Guthrie had a FIP of 5.66, 4.33 K/9, and 3.21 BB/9. Per usual, his ERA was still just 4.25. Many Royals fans, including myself, were extremely worried that Guthrie was about to run out of magic beans and see some significant regression to the mean.

As it turns out, his peripherals were just about to see some progression to the mean.

In the 2^nd half of the season, Guthrie has a FIP of 2.99, 6.53 K/9, 1.76 BB/9, and an ERA of 4.06. To give you an idea of how good he’s been since the break, here are some pitchers that Guthrie has outperformed according to FIP:

David Price

Stephen Strasburg

Zack Greinke

Cliff Lee

Chris Sale

And 85 other qualified starters, including every other qualified starter on the Royals roster.

Going by fWAR, Guthrie has been the 7^th most valuable starter in the league in the 2^nd half (1.4). The list of pitchers tied with, or ahead of Guthrie, is pretty impressive:

Doug Fister

David Price

Felix Hernandez

Anibal Sanchez

Yu Darvish

Max Scherzer

The only area where Guthrie lags behind is in his ERA, which is the 38^th lowest number among 56 qualified AL starters. (Although he does still beat Hernandez and Justin Verlander in 2^nd half ERA.) But using some advanced metrics shows that Guthrie is pitching extremely well since the All Star break.

But how is he doing that?

My first thought was that it was nothing more than his typical BABIP luck. However, his 2^nd half BABIP of .361 is actually the 2^nd highest number in the league. One could argue that Guthrie has been rather unlucky, although he has allowed an extremely high percentage of line drives (27.6%, highest in the league since the break), so a higher BABIP is to be expected. I’m guessing that both numbers start to normalize to more closely resemble his career averages, which could help his results dip down closer to what his peripherals suggest they should be (That’s a statement I never expected to write about Guthrie).

Where Guthrie may be getting some luck is in the home run department. He’s always been a pitcher who gives up his fair share of home runs, but Guthrie’s 1^st half HR/FB rate of 14.5 was still higher than you’d like to see. Since that number was higher than his career number, I expected a bit of regression, although I didn’t expect it to drop off a cliff like it has in the 2^nd half. Guthrie has a post-All Star break HR/FB rate of just 5.6. Along with that, he’s getting a higher percentage of infield flyballs (13%), which are usually not effective for hitters trying to get on base. Add that up, and you can see a part of the reason for Guthrie’s improved performance. But his resurgence isn’t all just dumb luck from the Batted Ball Fairy.

The jump in Guthrie’s strikeout rate made me think to dig into his pitch usage rates to see if anything has changed as the season has gone on. In the 1st half of the season, Guthrie’s pitch usage looked like this:

And here is his pitch usage since the All Star break:

As you can see, he’s been throwing a few more fastballs and more changeups, while throwing fewer sliders and curveballs. The other thing you may notice is Guthrie’s getting more movement with his changeup. With the increased movement, he’s gotten a few more swings and misses, with a pre-All Star break changeup whiff rate of 5.33%, and a post-All Star break whiff rate of 7.73%. Still not a very high mark, but it is improved, which may be why he’s throwing more changeups in the last couple of months. Guthrie is also getting more swings and misses on his sinker (5.94% in the 2^nd half, just 3.36% in the 1^st), so again, you would expect a slight uptick in usage for that pitch.

With all that being said, I think the biggest difference for Guthrie since the break has been his fourseam fastball. In the first half, opposing batters swung and missed at just 4.41% of his fourseam fastballs. In the second half, that number has jumped all the way to 12.28%. While his velocity has gone up a little, it isn’t significant enough to suggest that the increase is the sole reason for such a dramatic spike in his whiff rate. There has to be more to why Guthrie is missing so many more bats recently. With that in mind, here is Guthrie’s fourseam fastball zone profile from the first half (the zones where a pitch was thrown more frequently are red, while the less frequented zones are blue):

Now compare that to his fastball zone profile from the second half:

Basically, Guthrie was throwing far too many fastballs down the middle of the plate in the first half, which isn’t a very good strategy for success in the major leagues. He’s now throwing more fastballs up above, and on the periphery of the zone, which is resulting in a higher whiff rate, which is resulting in more strikeouts, which is resulting in lower blood pressure for Royals fans during Guthrie’s starts.

Even when hitters are making contact with the fastball, they aren’t doing much with it. Guthrie is allowing an isolated slugging percentage of just .053 off of his fourseam fastball since the break. Essentially, this means that Guthrie has turned opposing hitters into Chris Getz with his fastball. Prior to the break, that ISO was at .152, which is a similar number to that of Alex Gordon. You may not know this, but facing Getz is typically a far more appealing option for pitchers than facing Gordon.

Mandatory Credit: John Rieger-USA TODAY Sports

Take everything together, and you can see why Guthrie is having such an improved 2^nd half. Obviously the typical “arbitrary endpoints” caveats still apply, and his full season numbers are still decidedly mediocre, but the question now becomes:

Can he sustain this recent performance?

Quite honestly, I have no idea. Overall, some numbers seem to be headed for regression (HR rate, K rate), while others should improve (LD%, BABIP). My best guess is Guthrie reverts back to what he has been for his entire career: a guy with poor peripherals and enough magic beans in his pocket to keep him with an ERA right around the league average, and maybe a tick above. If he is able to continue putting up performances like he has since mid-July, that 3 year deal he is signed to could start to look a bit more palatable for the Royals and their fans.