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06/15/12 10:10 PM ET

Ross to start Saturday in McCarthy's place

OAKLAND -- A's manager Bob Melvin confirmed before Friday's game against the Padres that right-hander Tyson Ross would be called up from Triple-A Sacramento to start on Saturday in place of injured starter Brandon McCarthy. No official announcement had yet been made by the team, and no corresponding roster move has been announced.

Oakland knew it would need a starter to pitch for McCarthy since it was revealed that the righty was again experiencing soreness in his pitching shoulder after his last start, the same injury that has troubled him all season.

The good news for the A's is that a bullpen session for McCarthy on Friday went well, and Melvin reiterated that McCarthy shouldn't have to return to the disabled list. Melvin said the team is "hoping" that the right-hander will be able to make a start early next week. McCarthy's next scheduled turn in the rotation is next Friday against San Francisco.

Ross will return to Oakland for his second stint with the team. The 25-year-old is 2-6 with a 6.51 ERA in nine starts for the A's this season, and was 1-6 with a 7.34 ERA over his last seven starts. Ross was optioned to Sacramento on May 31.

In his two starts for the River Cats since being sent down, Ross allowed two earned runs in 13 innings.

"Last couple times out, he's done well," Melvin said. "Doing all the things that we've asked him to do, whether it's breaking balls, whether it's pitching inside and so forth. When we reached down for someone to start, all signs pointed to him, and we're pretty encouraged by the way he's been pitching."

Cespedes not in lineup, remains day to day

OAKLAND -- Outfielder Yoenis Cespedes wasn't in the A's lineup for Friday's series opener against San Diego, but manager Bob Melvin said that his cleanup hitter could return Saturday or Sunday, likely at designated hitter.

Cespedes originally strained his left hamstring on June 7 against Texas, and then aggravated it in his first game back on Wednesday against Colorado. The team's return to the Coliseum and American League rules means that Melvin again has use of the DH, which would be ideal for Cespedes because he wouldn't have to put stress on his hamstring playing in the field.

"I think we're going to probably run him around a little today," Melvin said Friday. "Whether it's tomorrow or the next day [that he returns], I'm not sure. It literally is day to day. We feel like we have a few more options with potentially being able to DH him here."

Melvin often has pointed to the impact that Cespedes' presence has on the A's offense, and there seems to be something to that. Oakland is 20-16 with the Cuban native in the lineup and just 9-19 when he has sat out. Cespedes was on the disabled list with a strained left hand before returning on June 1 and was 10-for-26 since then. The rookie is hitting .273 overall this season with six home runs.

"He's a guy that's very important to our lineup, and we feel like even though it didn't look great the other day, I think it scared him a little bit," Melvin said. "As far as his strength and everything goes, it's pretty good. We don't feel like we're in a DL situation right now."

Worth noting

• A's manager Bob Melvin flipped his two hitters atop the order in Friday's game. Outfielder Coco Crisp was hitting leadoff, while second baseman Jemile Weeks was moved to the second position.

• Left-handed reliever Jordan Norberto is scheduled to throw a bullpen session on Sunday and could be activated from the disabled list Tuesday. Norberto, who has a strained left shoulder, was eligible to come off the DL on Friday.

Ben Estes is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.