CINCINNATI – Reds starting pitcher Brandon Williamson announced Wednesday that he suffered a complete torn ACL and will require Tommy John surgery.

The left-hander had to leave Tuesday night’s game against Atlanta in the second inning with an elbow strain. He briefly doubled over near the mound and was replaced by Fernando Cruz.

“It kind of came out of nowhere,” Williamson said, adding that he had two MRIs to diagnose the tear.

Williamson, a second-round pick in the 2019 amateur draft, injured his shoulder in spring training. The 26-year-old made his first major league start of the season on September 1, the first of four starts this year.

“It was just baseball in the first inning,” Williamson said. “I would say I didn’t feel a little weird physically. Technique-wise, I may have changed a little bit. In the second inning, I came out after a long first inning and felt like I needed to put in a little more to warm up and get going. Another long first at-bat. There were no warning signs for me. I felt good. I think the third pitch (to Michael Harris II) I threw a changeup. I felt a little tug. I tell everyone, when you’re a pitcher, you feel things all the time. I didn’t think much about it. So the next pitch, I just felt it.”

Williamson allowed three runs in 13 innings in three appearances before Tuesday. Before his injury, he allowed three runs in the first inning. He finished the season with a no-hit record and a 3.77 ERA.

“He’s still young and athletic,” Reds manager David Bell said. “Obviously he’s not going to be on the mound on opening day. I don’t have any specific information on the timeline. I think once we know, hopefully we can realistically target having him back next year when there’s real time left in the season.”