Valera (calf) started in right field for Triple-A Columbus on Wednesday and went 0-for-4 with a walk.
Valera had been scheduled to begin a rehab assignment Tuesday, but it was pushed back a day. He last appeared in a game for the Guardians during spring training on March 9 and likely will need a few more plate appearances while on rehab. Once ready to go, Valera is expected to rejoin the Guardians.