Casilla's injury comes just as it seemed like he was getting a chance to break into the starting lineup. The switch hitter was 2-for-3 with two RBIs, one walk and one run scored in Sunday's 10-7 win and made an acrobatic tag of Tampa Bay's Desmond Jennings as he attempted to steal second.
Since the beginning of May, Casilla has started nine of the 18 games he's appeared in and batted .229 with five RBIs in those games. In that span, he's started back-to-back games only twice.
"Everything happens for a reason," Casilla said. "I don't want to be mad about this because everything happens for a reason. I've got to try to stay calm and patient and I'll be ready to play any time my finger lets me play."
For now, though, it's a waiting game for Casilla's return.
"I'll be fine tomorrow," Casilla said. "I've just got to let the medicine work."