On Tuesday, Diamondbacks manager Torey Lovullo announced Taijuan Walker had a UCL injury and would seek a second opinion in New York.
On Wednesday, Lovullo announced that injury is a tear and he will undergo Tommy John surgery.
Walker has a 4.02 earned run average in 170.1 innings in two years with Arizona.
Matt Koch will start in place of Walker on Friday.
Sports360AZ
