Updated: 5/22/2014 3:48 pm
Denver, CO (SportsNetwork.com) - San Francisco Giants reliever Santiago Casilla is expected to miss about a month after straining his right hamstring during Wednesday's game against the Colorado Rockies.
Casilla sustained the injury while running out a ground ball in the top of the ninth inning of the Giants' 5-1 win. The team placed the right-hander on the 15-day disabled list prior to Thursday's matchup with the Rockies, with reliever George Kontos recalled from Triple-A Fresno to take his place.
The 33-year-old Casilla has been one of the Giants' most dependable arms out of the bullpen this season, recording a 1.37 earned run average and one save over 22 appearances.
San Francisco received more encouraging news on the status of Matt Cain, who also departed Wednesday's contest with a right hamstring injury. The three- time All-Star was diagnosed with a Grade 1 strain and has yet to be ruled out for his next start.
If Cain, who tossed three hitless innings before being forced out, cannot take his next turn in the rotation, Yusmeiro Petit will likely draw the assignment. Petit earned the victory on Wednesday after throwing three scoreless frames in relief of Cain.