OAKLAND -- A's manager Bob Melvin said right-hander Tyson Ross, who has struggled in two rehab outings with Triple-A Sacramento, will make at least one more Minor League appearance before being considered ready for a return to big league action.

Ross (left oblique) tossed 3 1/3 innings for the River Cats in Fresno on Tuesday, utilizing 71 pitches along the way. He gave up four runs on seven hits, including a home run, and walked two with four strikeouts.

"He's struggling as far as results go," Melvin said. "One, it's about getting his pitch counts up there, and also about getting more ups and downs in the game."

There is no indication whether Ross will slide back into Oakland's rotation or be placed in the bullpen upon his return after the All-Star break, though Melvin said relief work is a definite option for the righty.

Balfour to be activated before Thursday's game

OAKLAND -- The A's will kick off a pivotal four-game road set in Texas beginning on Thursday with right-hander Grant Balfour in tow.

Manager Bob Melvin confirmed on Wednesday morning that the plan is to activate the reliever from the disabled list at that time, at which point righty Graham Godfrey is likely to be optioned.

Balfour, nursing a strained right oblique back to health, tossed one inning for Triple-A Sacramento in a rehab appearance on Tuesday, giving up one run on two hits with a walk while throwing 23 pitches, 12 for strikes.

"I'm ready to go," he said. "I'd go today if I could."

Balfour has held opponents to a .198 batting average this season, including .136 with runners in scoring position, and was tied for second among American League relievers in wins (four) at the time of his injury.

Willingham likely to return on Thursday

OAKLAND -- Following his club's 2-0 win over the Mariners on Wednesday, A's manager Bob Melvin delivered more good news by hinting that Josh Willingham is likely to make his long-awaited return from the disabled list on Thursday.

"If he doesn't hurt himself tonight eating dinner or whatever, I feel like there's a good chance he'll play [Thursday]," the skipper said.

The timing couldn't be better for the A's, who are set to begin a four-game set on Thursday in Texas, where warm weather and a hitter-friendly ballpark could make for the perfect ingredients for Willingham's power bat.

The A's outfielder, who has been sidelined by a nagging Achilles injury, leads the team with 10 home runs, and his presence has been missed in a struggling lineup that scored just five runs in the three-game series against Seattle.

Oakland is not expected to officially announce the move, or any other corresponding transaction, until Thursday.

Worth noting

With a 4-2 loss in the 10th inning on Tuesday, the A's fell to 5-10 in extra-inning games, which is the worst record in the American League.