Casey Mize’s First Inning Woes: Does He Need an Opener?

Bumpy Return for Casey Mize

Casey Mize was originally drafted 1st overall out of Auburn in 2018. He was the first Detroit Tigers draft pick after the rebuild became official in the summer of 2017. He performed exceptionally well in the minors in 2019, including throwing a no-hitter in his first Double-A start, and eventually made his MLB debut during the COVID-plagued 2020 season.

Mize had a solid rookie year in 2021, accumulating 3.3 bWAR thanks to a 3.71 ERA over 150.1 innings pitched. Poised to build on that campaign, Mize instead saw his season halted early in 2022 due to elbow discomfort. After throwing 10 innings and starting an abrupt rehab game in Triple-A Toledo, he underwent Tommy John surgery.

Casey Mize is now 11 games into his 2024 campaign. Nearly two years after receiving Tommy John surgery, Mize is still adjusting to his newly reconstructed UCL with a 4.70 ERA and a 1.49 WHIP through 53.2 innings of work. 

What’s New with Casey Mize

The most noticeable about Mize this year is the uptick in velocity on his four-seam fastball. His heater is now averaging 95.5 MPH, up significantly from his 93.4 MPH average in his blunt 2022 season. But this might not be completely related to his Tommy John surgery. While he was out Mize also underwent surgery to fix a long lingering back issue.

Another noticeable change in Mize’s repertoire is his splitter usage. When Mize was an up-and-coming prospect, his splitter was projected to be a plus-plus pitch at the MLB level. However, that projection never materialized with the Tigers. His splitter never became a reliable putaway pitch for him, leading to a surge in slider usage.

Flash forward to 2024 and his splitter is being used more than ever, with mixed results. In contrast to his rookie year, he is throwing his splitter 19.3% of the time, up 6.1% from 2021, and it’s producing a .286 wOBA against. Mize’s splitter is also getting more swings and misses, with a 31.3% whiff rate in 2024 compared to 22.2% in 2022. 

On the other hand, when not missing bats, Mize’s splitter is getting hit hard. Batters are producing a hard hit rate of 52.8% and an xSLG of .477 against the offering. This certainly isn’t ideal, but getting Mize back in the groove of consistently throwing his best secondary pitch is a step in the right direction. 

Casey Mize Struggles in the 1st Inning

Casey Mize has had a rough go of it during his first two months back from Tommy John. A 4.70 ERA isn’t the prettiest thing to look at, but is it really that bad? As I looked into Casey Mize’s splits, something stood out: his 1st innings are rough.

The chart below shows his statistics in the 1st inning compared to every other inning he has pitched this year. You will probably notice a pattern quickly.

Casey Mize is having fits in the first, just about any way you slice it. The discord between his ERA is very noticeable, and he is walking almost twice as many batters in the first frame.

Mize has allowed first-inning runs in 5 of his 11 starts this year. The Tigers 2-3 in those outings, and 4-2 when Mize manages a clean first inning. But even when he doesn’t allow a run in the first inning, Mize is running into another issue: pitch count.

Any pitcher’s ERA can look pretty if they pitch 5 scoreless innings per start, but we live in an age where bullpens are being relied on more than ever. Starting pitchers throwing that extra 6th or 7th inning can be crucial for a pitching staff. Casey Mize averages 4.2 fewer pitches thrown in innings other than the 1st. If the Tigers eliminate the 1st inning of work for Mize it might allow him to get a better feel for his stuff, while also putting the club in a better position to win.

One thing to note is that every number in blue on the chart above is slightly below league average. But maybe as the season progresses Chris Fetter and company can help build Mize back into the pitcher he once wase top prospect he once was.

There may be no way to directly help Mize fix his struggles right now. But there might be a way to help the Tigers win more games while still giving Mize his typical 5-6 inning. AJ Hinch can use an Opener.

What is an Opener?

An opener is a relief pitcher used at the beginning of the game, for a variety of strategic purposes. These reasons can be as simple as not allowing 1st inning runs, or not overworking starting pitchers, or allowing your regular starter to skip over the heart of the other team’s batting lineup.

It was first implemented in 2018 by manager Kevin Cash of the Tampa Bay Rays. The Rays had a 3.97 ERA in 2017, but that improved to 3.74 in 2018 and helped the Rays win 12 more games. The Tigers used an opener occasionally in 2019 under former skipper Ron Gardenhire. Current Tigers manager AJ Hinch has also used an opener during his tenure in Detroit, so using an opener for Mize certainly wouldn’t be Hinch’s first rodeo using the strategy. 

Is It Worth It?

There are a few different views to this. Casey Mize isn’t a free agent until 2027, but this past offseason the Tigers signed Mize to a one-year, $830,000 deal, with a $3.1 million team option for the 2025 season that includes a $10,000 buyout. Mize had been seeking $840K. 

The details of those negotiations deserve an article of their own, but the contract raises a few questions. How long of a leash does Casey Mize have if he continues to have a poor season? Do the Tigers want to continue to develop him, or is the focus on winning?

The Tigers have fresh arms in the minor leagues that can’t live there forever. Jackson Jobe is one of the best pitching prospects in baseball, when healthy. We’ve already seen Keider Montero in the majors this year, and Ty Madden and Troy Melton probably aren’t too far behind him. Can Mize be moved to the bullpen in the future to make room for younger arms?

The best compromise between the Tigers and the right hander is to use an Opener to allow Mize to continue to pitch at the big league level in big roles. This would let the Tigers to pursue a wild card spot for the first time in a decade, while still continuing development on a pitcher who has been dealt a bad hand but still boasts great potential.

The numbers support using an Opener, and the Tigers have the resources. It’s up to AJ Hinch and Scott Harris to weigh their options.