PHOENIX -- D-backs manager Torey Lovullo announced on Wednesday that right-handed pitcher Taijuan Walker will require Tommy John surgery to repair a partial tear of the ulnar collateral ligament in his right elbow.
Walker was most recently in New York seeking a second opinion from Dr. David Altchek. Shortly after, the D-backs learned of the bad news.
"It's terribly disappointing," Lovullo said. "I hurt for him, I think this organization hurts for him. … It's one of your players going down that we were going to count on. He's hurting. When he hurts, we all are. We're going to support him in the best situation we can, but this is a tough situation we're walking through."
Lovullo didn't have additional details on the tear or Walker's timetable (though it usually takes pitchers at least 12 months to recover). What he did say was that a conservative approach -- or non-surgical treatment -- to the injury wouldn't be the best bet.
Walker left his start against the Dodgers last Saturday with tightness in his right forearm and was originally placed on the 10-day disabled list on Sunday. He received a first opinion on the MRI from Dr. Gary Waslewski, the head team physician.

Matt Koch was scratched from his Wednesday start for Triple-A Reno and will be on the mound Friday -- originally Walker's day -- when the D-backs face the San Diego Padres. Koch, who was one of the final cuts in big league camp this spring, threw six scoreless innings in his only start in Reno this season.
"[He] threw the ball great in Spring Training, looked healthy and stronger than he did last year, velocity was up," Lovullo said.
However, Lovullo said he was unsure whether Koch would be the long-term answer. Especially because Shelby Miller, who is nearing the end of his own Tommy John surgery recovery, is expected to be back in late June.
When Miller injured his UCL last season and needed surgery, Braden Shipley and Zack Godley received opportunities. Godley ran with his and is now in the team's starting rotation.
"That could happen in this situation, we could end up using quite a bit of our depth [in our farm system]," Lovullo said.
The D-backs are currently without Jake Lamb and Steven Souza Jr. Yet, they're 12-4 and tied for the best record in the National League entering play on Wednesday.
When Lovullo announced Walker would need Tommy John, Walker was on a plane back from New York. Lovullo had no further update on when the surgery would be, or who would perform it.
Though Lovullo said he manages in the best interest of his pitchers' safety, Walker's situation shook him.
"I hurt thinking that I had a play in this," he said. "I got to come to a peaceful conclusion with that, and I'll probably feel better once I see Taijuan."
Lamb feels good after extended spring game
All signs seem to be positive with Lamb, who continues to recover from an AC joint sprain in his left shoulder.
On Wednesday, Lamb played five innings at third base and had five at-bats in an extended spring game. He went 2-for-4 with a walk and made a nice backhanded play in the field.
And this happened:
"Caught a ball from the catcher, it took me up the line and the guy ran into me, didn't slide, so that was a test in itself," Lamb said.
The real test, Lamb said, comes when he's at the plate.

"When you're trying to hit a 2-0 fastball and you get a changeup, get completely fooled, left shoulder extends, that's going to be the one that's going to hurt," he said. "And it didn't at all."
Lamb said he felt good, but Lovullo doesn't know for sure whether he'll be back by next week when the team begins a road trip in Philadelphia.
"We like what we're seeing out of him, but once again, we're not going to fast forward anything and put him in a situation where he's not going to be ready and we go backwards," Lovullo said.
Lovullo said he likes rehab assignments because they offer more than a simulated game or live batting practice. But on Wednesday, he alluded to being satisfied with Lamb's participation in extended spring games, as long as the third baseman doesn't experience any setbacks.