The pitcher left Saturday's game with tightness in his forearm.
Diamondbacks pitcher Taijuan Walker will have Tommy John surgery, the team announced Wednesday.
The surgery is reportedly due to a partial UCL tear.
Taijuan Walker will have Tommy John surgery. Partial UCL tear.— Zach Buchanan (@ZHBuchanan) April 18, 2018
Walker had an MRI taken on Tuesday that showed injury to his UCL, and he flew to New York to get a second opinion, according to MLB.com.
Walker left Saturday's game against the Dodgers with forearm soreness. He began to feel it during the first inning but did not leave the game until the end of the second inning.