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Part One: Astros’ Starting Pitching a Concern heading into Postseason?

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Regression to the mean, or something else?

Chicago White Sox v Houston Astros Photo by Bob Levey/Getty Images

Let’s be clear: the Houston Astros have the best starting rotation in Major League Baseball, possibly the best the league has seen in many years (e.g., MLB.com; Washington Post; FanGraphs). Two starters (Justin Verlander and Gerrit Cole) have been Cy Young-worthy all season and another (Charlie Morton) had been in the mix until recently. Verlander and Cole are 1-2 in the American League in strikeouts and Morton leads the Majors in Win-Loss percentage (0.824). The Astros have also had phenomenal health with their starting pitchers. Three guys (Verlander, Cole, and Dallas Keuchel—two of which are previous Cy Young award-winners) have made 30+ starts (Morton, who currently has 27 starts, should have at least 30 by season’s end as well) and each member of the original five-man rotation made his scheduled start through the first four months of the season.

However, the starting pitching has looked vulnerable of late. Verlander and Cole haven’t been able to go deep into games with regularity like we saw early in the season, and Morton has dealt with control issues (and a brief stint on the disabled list). As we near the postseason, an important question is whether the recent struggles by the starters are simply a change in fortune for the Astros, or indicative of an adjustment opposing teams have made? In Part One of this two-part series, I will overview the performance of two of the four pitchers anticipated to make starts for the Astros in the postseason; Part Two will explore the other two expected playoff starters.

The Ace - Justin Verlander

89th MLB All-Star Game, presented by Mastercard Photo by Rob Carr/Getty Images

1st Half: 137.2 IP, 2.29 ERA, 2.84 FIP, 3.49 xFIP, 27.9% K-BB Rate, 1.05 HR/9, 8.9% HR/FB, 16 HR allowed, .241 BABIP

2nd Half: 57.1 IP, 3.37 ERA, 3.23 FIP, 2.47 xFIP, 31.6% K-BB Rate, 1.73 HR/9, 18.3% HR/FB, 11 HR allowed, .364 BABIP

Right before the All-Star Break, Verlander was rolling along at 9-4 with a 2.05 ERA. Then, in his final start before the Break, he tied a career-high by allowing four home runs to a Detroit Tigers team in the bottom five of MLB in homers. Although he still struck out 12 batters, the performance left even Verlander bewildered.

Following the Break, Verlander sandwiched a couple of splendid starts in Los Angeles against the Angels and Dodgers around an okay one against the Texas Rangers. Then came the meltdown against the Seattle Mariners, in which he allowed three homers and six runs in two innings before eventually getting tossed.

MLB: Seattle Mariners at Houston Astros Troy Taormina-USA TODAY Sports

The trouble Verlander had with the longball against the Tigers foreshadowed what has become a lingering issue. Over a span of six starts from July 28 to August 25, Verlander surrendered at least one home run in each game, and multiple homers in half of them. In the month of August, Verlander gave up 9 homers in 32.1 IP, posted a 5.29 ERA, and allowed an opponent BA of .269—all season-worsts for a single month. The 27 home runs Verlander has allowed this season are the eighth-most in MLB and equals his total from 2017 (his career-high is 30 HR allowed, set in 2016). But he struck out 50 batters and walked only walked five in August while also posting his highest K/9 rate (13.92) and second-best K/BB rate (10.00), K% (37.00%) and BB% (3.70%) of 2018—he was as imposing in August as he had been all season. In fact, JV leads the Majors in K/BB rate this season (7.37).

Most pitchers, even the elite, Cy Young-contending ones such as Verlander, have a month in which they struggle relative to their overall season performance. For Verlander, was August simply regression, possibly attributable to the dog days of Summer, or has the league made an adjustment?

For one, JV didn’t strand runners in August (76.6% LOB%) at the same rate he has all season. I’m being nitpicky here, admittedly—league average LOB% is approximately 70-72%, depending upon the season—but Verlander’s LOB% in 2018 has been an excellent 84.2% (third in MLB), so the dip to about 77% in August takes him from excellent to merely above average (just outside Top 20 of starting pitchers if extrapolated over the course of the 2018 season).

FanGraphs suggests the use of LOB%, BABIP, and HR/FB in conjunction can help assess whether a pitcher is underperforming or overperforming and if regression is likely. Verlander’s BABIP was .366 in August, by far his worst of any month (.333 in July ranks second-worst). For context, Verlander’s overall BABIP in 2018 is .277, .287 over his career, and the average BABIP for pitchers is about .300, though season-to-season fluctuations are common. Thus, it appears Verlander’s BABIP was unexpectedly high for the month of August.

Verlander’s HR/FB rate in August was 22.5%, nearly identical to his season-worst 22.6% rate in July (which was mostly a result of his start against Detroit just before the Break). Verlander’s HR/FB rate has more than doubled in the second half (18.3%), compared to the first half (8.9%). His career HR/FB rate is 8.6%, though that number has jumped to 11.3% in 2018 (the second-highest of Verlander’s career, behind his 11.5% HR/FB rate from 2017, when he split time with the Tigers and Astros). We know the Astros have challenged Verlander to use the fastball more often than he did in Detroit. As we saw when Verlander gave up two home runs to Khris Davis in Oakland, he can be stubborn with his fastball usage, basically employing the old-school mentality ‘Hit it if you can.’

According to Baseball Savant, in 2018, Verlander has thrown the highest percentage of Meatballs (9.2%) in his career since pitch tracking began in 2015. A “Meatball” is defined by Brooks Baseball as “a pitch thrown in the middle-middle of the plate, regardless of movement or velocity,” or more easily understood as “an easy pitch to hit, right down the middle of the plate.” He’s still getting roughly the same percentage of swings on Meatballs as he has his entire career (77.4% in 2018 vs 76.5% since 2015); however, if he’s throwing Meatballs more often, the amount of swings against those are also increasing in frequency. And as one analysis from FiveThirtyEight showed, Meatballs tend to be the “most homer-friendly pitch.”

With all that said, it seems Verlander has made an adjustment in his pitch selection through two starts in September. Here’s a visual showing JV’s pitch type by month this season.

As you can see, Verlander relied heavily on the four-seam fastball in July/August, months in which he gave up homers at an alarming rate. He has massively curtailed that usage in September.

Granted, it’s only been 14 innings, but Verlander has allowed 9 hits and zero home runs in September. His strikeout rate is down slightly compared to July/August, but who cares when you’re fanning 18 batters in 14 innings. What I like is that Verlander is beginning to go deep into games again. Before the Break, Verlander pitched into the 7th inning 11 times; since then, he has only done so three times (but twice in two September starts). The Astros’ bullpen is better this year than last, but there’s nothing more assuring than your starters pitching deep into games in the playoffs.

I think we what have seen with Verlander since the Break is a combination of some expected regression based on his FIP and xFIP in the first half, and the league adjusting to the changes he has made since joining the Astros. Hitters are sitting on Verlander’s fastball; it’s up to him and the Astros to counter (and early September returns indicate they have).

The Other Ace - Gerrit Cole

Los Angeles Angels of Anaheim v Houston Astros Photo by Bob Levey/Getty Images

1st Half: 128.1 IP, 2.52 ERA, 2.98 FIP, 3.10 xFIP, 26.2% K-BB Rate, 0.98 HR/9, 11.8% HR/FB, .256 BABIP

2nd Half: 59.0 IP, 3.66 ERA, 2.24 FIP, 2.82 xFIP, 26.4% K-BB Rate, 0.61 HR/9, 7.7% HR/FB, .338 BABIP

Cole was humming along at the All-Star Break, going 10-2 with a 2.52 ERA. Just like Verlander, Cole has seen his numbers dip a bit since the Break. Oddly enough, many of Cole’s peripheral stats indicate he should be better in the second half than in the first. His FIP, xFIP, HR/9, and HR/FB have all improved and his K-BB% is essentially the same, but his ERA and BABIP have nonetheless risen. So, what’s going on with Cole?

Part of the issue is that he’s giving up more doubles. Cole allowed 17 doubles in the first half over 128.1 innings but has surrendered 16 two-baggers in only 59 innings in the second half. In fact, Cole gave up 12 doubles over five starts in August alone after allowing only 13 doubles in 16 starts spanning May to July. But Cole didn’t give up any homers over an eight-start span from July 9 to August 20 (53 IP). That’s likely because Cole has been allowing line drives per ball in play (BIP) on the heater at a much higher rate in August (36.11%) and September (42.86%) than previously, and far fewer flyballs per BIP on the heater (25.00% in August; 7.14% in September).

So even though hitters are not driving the ball out of the park against Cole, they are squaring him up often enough to do damage.

One indicator that strikes me for Cole is a change in the quality of contact he has given up lately. Quality of contact is separated into three categories: Soft, Medium, and Hard. According to FanGraphs, Cole has given up much more Medium contact in August and September than previously in 2018 (58.1% and 59.0% respectively). Likewise, Cole has allowed Medium contact at a higher rate in the second half (57.3%) than the first (46.0%). Although quality of contact is not a perfect proxy for runs allowed, it may provide some additional insight as to why Cole has underperformed in the second half, relative to his peripherals. He’s not getting crushed out there, he’s just simply permitting enough quality contact to get into trouble quickly (doubles can pile up). It likely comes as no surprise then that Cole’s LOB% has been much lower in the second half than the first (70.3% vs. 82.6%), primarily due to a 60.9% LOB in August when Cole was giving up all those doubles.

Providing the Astros with pitching length was also an attribute of Cole’s in the first half. However, he seems to be laboring to get through just five or six innings in recent months, and that concerns me. Cole pitched into the seventh inning in his first seven starts as an Astro and 10 times in the first half. He, like Verlander, has only done so three times in the second half (and not since August 10). I don’t have hard data to back up this assertion, but Cole seems to be getting into long battles with hitters that ultimately pushes his pitch count up. Cole has still been pretty effective, he just hasn’t been able to sustain his outings as the season has progressed.

Cole, to me, might be the most important guy for the Astros in the postseason. We’ve seen Verlander be great in big moments, both with the Astros and Tigers. Cole, who is a fantastic pitcher and likely in the midst of his best season as a professional, is more of a question mark when it comes to the playoffs. He’s made three postseason starts, all with the Pittsburgh Pirates, and his results have been a mixed bag (1-1, 3.94 ERA, 0.87 WHIP, 14 K’s in 16 IP, and 4 HR allowed). However, he’s arguably been the Astros’ best pitcher this year, so I have quite a bit of confidence in who he has become rather than who he was (which was still pretty stinkin’ good, anyway). Credit should be given to opposing teams for making Cole work to get outs, but I believe his recent dip in performance is due more to poor luck and fatigue than much else.