Valdez was placed on the 10-day injured list with a lower back strain Monday.
Valdez gave up two runs on three hits and a walk while striking out one in one inning during Sunday's loss to the Orioles, and it's possible that his injury contributed to his struggles. Whether he's forced to spend more than the minimum of 10 days on the injured list remains to be seen, but right-hander Travis Lakins was recalled in a corresponding move.