OAKLAND -- With the emergence of Bobby Cramer in the A's rotation, Vin Mazzaro has been relegated to the bullpen for the remainder of the season.

"I'll approach it the best I can," Mazzaro said. "Just do my job, stay loose, be ready in the bullpen for whatever happens."

Mazzaro, who will turn 24 on Monday, has made 22 appearances (18 starts) for the A's this season, but was sent down to Triple-A Sacramento on Sept. 6 after an eight-start stretch that saw him go 0-6 with a 5.60 ERA.

Mazzaro made one start with the River Cats before they were knocked out of the playoffs, and has made just one relief appearance in Oakland since then. He said the organization asked him to work on his changeup in Sacramento, but no major tweaks were made.

Looking ahead to next season, Mazzaro figures to be the front-runner for the fifth spot in Oakland's rotation, assuming the team keeps Trevor Cahill, Brett Anderson, Gio Gonzalez and Dallas Braden.

"He pitched in [the rotation] a lot this year," Oakland manager Bob Geren said. "He's young and talented, so he is definitely in the mix."

Geren added Mazzaro will be the club's primary long man for the next few days, as Boof Bonser has been used as the situational reliever in three of the past five games. Still, Mazzaro said he's focused on returning to the A's rotation next season.

"That's the whole goal," Mazzaro said. "I'm not a bullpen guy, I'm a starter. Hopefully, I'll be working in the starting rotation and the offseason goes well."

Blevins may be done for rest of season

OAKLAND -- Jerry Blevins expressed continued improvement in his sore left shoulder on Saturday, but the A's reliever admitted he very well may be done for the remainder of the season.

"Nothing's been determined or really even discussed yet," Blevins said, "but at this point, where we are right now, it might be best not to push it."

The A's entered Saturday's contest against the visiting Rangers standing eight games back, with nine left on the schedule. Texas needs just one win and an Oakland loss this weekend to clinch the American League West title, a feat that would likely shelve Blevins.

"The competitive part of you wants to be out there, wants to finish the season healthy," he said. "But this isn't something I've dealt with before, so we're trying to be careful."

Blevins underwent "more extensive" drills with A's strength and conditioning coach Bob Alejo on Saturday morning, but he's yet to resume throwing. The southpaw compiled a career-high 48 2/3 innings a year after he tossed just 22 1/3 innings in 20 appearances through three stints with Oakland in 2009.

Blevins had not allowed a run in seven of his past nine outings before he succumbed to the shoulder injury following his most recent appearance, a one-inning relief stint in Kansas City on Sept. 15. His absence will leave Craig Breslow as the lone lefty in an injury-ridden bullpen, which also lost Andrew Bailey to season-ending elbow cleanup surgery this past week.

Worth noting

Rajai Davis returned to the A's lineup on Saturday after missing two straight games due to what was deemed a "non-baseball-related issue." Manager Bob Geren declined to comment on the reason for his absence on the field, but assured it was not disciplinary-related. "Absolutely, 100 percent no," Geren said. ... Michael Wuertz said his sore right thumb has improved greatly. He was available Friday night and said he was good to go Saturday. ... Rookie Chris Carter entered Saturday's game having hit safely in each of his past five games (6-for-14) after going 0-for-32 over the first 11 games of his career, all of which came on the road.