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Adbert Alzolay's Ascension and Return

Highlighting how Adbert Alzolay has made improvements to his pitch arsenal and why he's so important to the Cubs starting rotation.
Adbert Alzolay Cubs

Photo: Cubs/Twitter

We’ve come a long way since Adbert Alzolay was spotted in the dugout taking notes in between innings of his MLB debut in 2019. He’ll make his return tonight versus the Cleveland Indians after a brief stint on the injured list due to a blister. Alzolay has a 4-5 record with a 4.06 ERA and 1.04 WHIP in 11 starts and 57.2 IP. But wait, there’s more. How good has Alzolay been exactly, and what does his return to the rotation mean? Let’s dive into the numbers and attempt to answer.

Echoed in recent interviews by David Ross, Adbert Alzolay has legitimate strikeout stuff. He has the second-best K/9 rate among regularly used Cubs starting pitchers this season with a 9.68 K/9. What’s really helped Alzolay has been his ability to limit walks. Despite allowing five in his most recent start where he was obviously dealing with a blister, Alzolay ranks second among team starters to only Kyle Hendricks with a 2.50 BB/9 rate. To get the control results he was looking for, Alzolay has reinvented himself.

Alzolay's Ascension

The increase in slider usage has seemed to make the biggest difference. Alzolay’s slider was his most seldom used pitch last year at only 6.7 percent. This season, he throws it more than any other pitch at 46.9 percent. Along with that, he’s basically eliminated the curveball and changeup from his arsenal entirely. Combined, he’s thrown his curve and changeup only 4.7 percent of the time.

There’s also been a conscious effort to throw more sinkers and fewer four-seam fastballs. Last season, he threw his sinker 20.7 percent compared to 31.5 percent four-seamers. This year, he’s done almost the exact opposite — 29.3 percent sinkers compared to 19.1 percent four-seamers.

The question is why? More control and better tunneling. The slider/sinker combo plays nicely off each other, whereas the curveball/slider mix seemed to be harder on him to get consistent feel for each one individually. And the four-seamer can still be a weapon because of the ride and velocity, but it’s been effective when used properly with better pitch sequencing.

The sinker/slider combo has also led to a 45 percent groundball rate, which is the highest of his career, including any stop at the minors. Now, it goes without saying, but I’ll mention it anyway. Groundballs help induce double plays and avoid big innings, but they also help limit serious damage like home runs and extra-base hits that usually come from balls hit in the air.

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For a 26-year-old with limited Major League pitching experience, Alzolay hasn’t shown signs of fear. He’s pitching like a veteran who trusts his stuff and is on constant attack. His 63.8 percent first-pitch strike rate is a 12 percent improvement from last season. Simply put, he’s getting ahead in counts more times than not. With a 52.4 percent in-zone pitch percentage, he’s improved annually since 2019 when that number was 42.2 percent. Batters realize this and they are swinging more than ever against him (47.5 percent swing rate).

However, that hasn’t improved their contact rate against him and they are actually swinging at more pitches outside of the zone (28.3 percent chase rate compared to 26 percent last year). As aforementioned, batters are swinging more in general against him, but the contact rate on pitches he’s thrown in the zone is 79 percent, three percentage points lower than league average.

In summary, while his control and command have improved, his deception has followed. Batters are whiffing at a career-best clip (28.2 percent) and Alzolay’s swinging strike rate is also a career-high (12.1 percent).

Let’s go back to the slider for a second. Alzolay finds himself in great company among the pitch type leaderboard. His slider is tied with Carlos Rodon for fourth among run value leaders with a -10. The pitchers ranked above them are Clayton Kershaw (-12), Joe Musgrove (-12), and Yu Darvish (-11). I’m not saying he’s on Darvish’s level, or any of the others mentioned, but if that’s a sign of how good that particular pitch has been, it’s no wonder why he’s made such a significant change to his pitch mix.

Alzolay’s slider has already fanned 40 batters. He struck out a total of seven on that pitch a year ago. That said, he only threw it 26 times last year. It was something he and the Cubs worked on toward the end of last season. “We got a new grip on the pitch so I can stay behind the ball longer,” Alzolay said.

Return to the Rotation

Alzolay will be making his return to action tonight against the Cleveland Indians. His presence in the rotation is much needed, given the rest of the staff’s recent struggles. Jake Arrieta is 5-8 with a 5.45 season ERA and a disgusting 7.22 ERA in his last seven starts. xFIP is a good indicator of how a pitcher is going to perform. Alzolay leads all Cubs starters with a 3.60 xFIP and 0.6 fWAR. As a whole, the Cubs rotation is dead last in fWAR (1.2) and has the fifth-worst K/9 (7.63).

It’s safe to say the Cubs really need him healthy and pitching well, especially because we have no idea if they are going to make any major pitching additions at the trade deadline or who those possible reinforcements would be. Given that Alzolay has never pitched more than 120.1 innings at any level in his professional career, the blister that sent him to the injured list could wind up being a blessing in disguise. The Cubs certainly don’t want to overtax him, and that could allow them to keep him on the mound late in the season and late in games when they start to count.