LOS ANGELES -- Clear issues are developing at the back end of the Los Angeles Dodgers' rotation.

Dan Haren and Josh Beckett have a combined 8.33 ERA since the All-Star break, and the Dodgers lost five of their past six starts.

The team made a move Monday that could provide a fallback option. Right-hander Carlos Frias was promoted from Triple-A Albuquerque. Frias, 24, took the roster spot of reliever Chris Perez, who went to the DL, and he will be available to pitch in long relief.

Frias' real value is as a ready replacement should Beckett or Haren be bumped from the rotation. Dodgers manager Don Mattingly said that only would happen for physical reasons, not a performance-related change.

"He's going to be in our bullpen," Mattingly said. "He's built up to start. He's been starting all year long. If something went wrong like an injury or somebody couldn't make a start, assuming he hasn't been used for three innings the day before or two innings the day before that, he would be a guy who could possibly do that."

Beckett struggled with a hip problem for weeks and went on the DL in July as a result. He received a cortisone injection at the time and has not pitched well since returning.

Haren has no apparent physical problems, but he has a 6.52 ERA since the end of May.

Frias was 8-4 with a 5.01 ERA in 16 appearances (15 starts) at Triple-A Albuquerque this season. He made his major league debut with two scoreless relief innings Monday in the Dodgers' 5-0 loss to the Los Angeles Angels.