CHICAGO — The Cubs provided more details on the operation that ace Justin Steele underwent Friday.

Steele had a left ulnar collateral ligament (UCL) revision repair operation under Dr. Keith Meister. It wasn’t Tommy John surgery — a reconstruction of the UCL — but Steele still will be out through 2025.

[MORE: Justin Steele sends message to Cubs fans before surgery]

“We’re looking at kind of about a year timeframe,” Cubs manager Craig Counsell said before Saturday’s game against the Arizona Diamondbacks at Wrigley Field. “Obviously, he’s got a long rehab ahead of him, and he’ll get started soon and he’ll put all the work in, and we’ll see where that gets us.”

Steele soon will head to Arizona to begin his rehab process at the team’s complex in Mesa.

Atlanta Braves right-hander Spencer Strider suffered a damaged UCL in his elbow in April 2024 and underwent an internal brace surgery by Meister. Strider missed the rest of last season, but he made his first appearance of 2025 on Wednesday, allowing two runs on five hits with five strikeouts in five innings. That could be somewhat of a guide for Steele in his recovery.

Tommy John surgery would have put him out in the 14-month range. Cubs right-handed reliver Ethan Roberts underwent the procedure in late 2022, missed the 2023 campaign, returned to pitch early last season and was in the majors by last summer.

Steele had his best outing of the year on April 7, tossing seven scoreless innings with eight strikeouts and allowing just three hits. He landed on the 15-day IL with elbow tendinitis two days later, though, and underwent an MRI. It was deemed he needed an operation after receiving second opinions.

The Cubs were unsure of the extent of the surgery until the doctors were able to get in and assess the severity of the injury.

Steele’s absence creates a massive hole in the Cubs’ rotation, but right-hander Colin Rea, who slotted in his place after he went down, has been solid in his first two starts. The 34-year-old has allowed two runs in 8.1 innings against the Diamondbacks and the Los Angeles Dodgers, and has a 1.32 ERA in 13.2 innings this season.

Injury update

• Counsell said right-hander Eli Morgan (right elbow impingement) underwent an MRI and is receiving second opinions. He was placed on the 15-day IL on Tuesday.