Former No. 1 overall pick Casey Mize to undergo Tommy John surgery

Casey Mize was a key part of the Detroit Tigers' rebuild. Now he figures to be sidelined for at least a year.

Tigers manager A.J. Hinch told reporters Friday the right-hander, selected first overall in the 2018 MLB draft, will undergo Tommy John surgery, according to the Detroit Free Press. The surgery figures to sideline Mize for the rest of the 2022 season and most if not all of 2023.

Mize has not pitched in an MLB game since April 14, when he was placed on the injured list with an elbow sprain. He attempted a rehab assignment in mid-May, but was ultimately put back on the shelf.

Curiously, Hinch said Mize does not have a torn UCL, the ligament replaced in Tommy John surgery. Rather, the ligament has apparently lost its elasticity, requiring a new one.

"He still doesn't have a torn ligament," Hinch said. "Dr. Meister has diagnosed him with a stretched ligament that's lost its elasticity and functionality inside his elbow. Any of the exams we've had, it's shown an intact ligament, which is true. But the symptoms continue to recur."

This development is a major step back for Mize, whom the Tigers were hoping would be their ace of the future when they picked him out of Auburn over the likes of Joey Bart, Alec Bohm, Nick Madrigal and Jonathan India.

A consensus top-30 prospect entering the 2020 and 2021 seasons, Mize has seen middling results so far in his MLB career, holding a 4.29 ERA, a 4.95 FIP, a 1.208 WHIP and 148 strikeouts in 188.2 innings pitched (39 starts).

DETROIT, MI -  SEPTEMBER 24:  Pitcher Casey Mize #12 of the Detroit Tigers during the third inning of a game against the Kansas City Royals at Comerica Park on September 24, 2021, in Detroit, Michigan. (Photo by Duane Burleson/Getty Images)
Casey Mize figures to miss most of next season, if not all of it, for the Tigers. (Photo by Duane Burleson/Getty Images)