Dodgers pitcher Tony Gonsolin to undergo Tommy John surgery

Dodgers right-hander Tony Gonsolin will undergo Tommy John surgery to repair a torn ulnar collateral ligament in his elbow on Friday, the team announced before Monday night’s game against the Arizona Diamondbacks in Chavez Ravine.

The procedure, which will be performed by Dr. Neal ElAttrache, typically requires a 12- to 16-month recovery, so Gonsolin will be sidelined for all of 2024.

Gonsolin, 29, was placed on the 15-day injured list because of right forearm inflammation on Aug. 19, one night after he gave up a career-high 10 earned runs and five homers in 3 ⅓ innings of an 11-3 loss to the Miami Marlins that dropped him to 8-5 with a 4.98 ERA in 20 starts on the season.

An MRI test last week confirmed the UCL tear, which Gonsolin had been pitching with for more than a month.

Gonsolin missed the final five weeks of the 2022 season because of a right forearm strain and the first four weeks of 2023 because of a left ankle sprain.

He returned in late April but he never regained his 2022 All-Star form, muddling his way through this season with a diminished fastball and a four-pitch mix that wasn’t nearly as crisp as it was last season, when Gonsolin went 16-1 with a 2.14 ERA in 24 starts.

Manager Dave Roberts had made vague references to Gonsolin “not being 100%” for several weeks, but the Dodgers thought Gonsolin turned a corner with an Aug. 12 start against Colorado, when he responded to a first-pitch homer by Ezequiel Tovar to throw six two-hit, shutout innings with six strikeouts and no walks in a 4-1 win.

But it wasn’t until Gonsolin was shelled by the Marlins in his next start — Gonsolin had not given up more than five earned runs or two homers in any of his 70 previous career starts — that Roberts acknowledged for the first time publicly that Gonsolin has been dealing with an “arm issue” for four to six weeks.

The manager said the team’s medical staff assured him that Gonsolin would not do any further damage to his elbow by continuing to pitch, and there was substantial financial incentive for Gonsolin, who avoided arbitration by signing a two-year, $6.65-million contract last winter, to pitch through discomfort.

Gonsolin’s contract includes incentives that increase his 2024 base salary of $3.4 million based on points earned in 2023, with one point per start and one point per relief appearance of 3 ⅓ innings or more, and $500,000 awarded for each of 14, 16, 18, 20, 24 and 28 points.

With the 20 points he accrued with his 20 starts, Gonsolin boosted his 2024 salary by $2 million, from $3.4 million to $5.4 million.

The velocity of Gonsolin’s four-seam fastball has dropped steadily over the last three seasons, from an average of 95.1 mph in 2020 to 93.8 mph in 2021, 93.1 mph in 2022 and 92.4 mph in 2023.

Gonsolin said this season’s injury impacted his stuff more than command. Roberts said it was difficult to determine how much of Gonsolin’s struggles were performance-related or injury-related.

“I think it’s a combo, like most things,” Roberts said on Aug. 19. “I do think there’s something with the mechanics that over time gets changed and manipulated. So I don’t think there’s a really clear answer, but I think all of it has led to the inflated ERA.”

Gonsolin will be the third Dodgers starter to undergo Tommy John surgery in the last two seasons, joining right-handers Walker Buehler and Dustin May.