Updated

Tyson Ross is making it hard on his manager.

Bob Geren needs to pick a fifth starter, and Ross hasn't done anything to eliminate himself from consideration.

Well, almost anything. He did finally give up a run on Thursday, in another stellar outing in Oakland's 15-7 win over Arizona.

"He's throwing the ball well," Geren said. "He was so efficient today."

Ross gave up one run on four hits in 5 2-3 innings. It was the first run the 6-foot-6 right-hander has allowed in 15 1-3 innings this spring.

"I liked the command of his fastball," Geren said. "That's the key to his success. The velocity and movement is always there."

Kurt Suzuki and David DeJesus each had three RBIs and Kevin Kouzmanoff hit a solo home run and added an RBI single for Oakland.

Ross is in contention with Brandon McCarthy and Bobby Cramer. McCarthy has a 3.05 ERA, 14 strikeouts and zero walks in 20 2-3 innings this spring. Cramer has an 8.25 ERA with five strikeouts and four walks in 12 innings.

"My sinker was pretty good when (catcher Suzuki) called it, and I threw some changeups in there to get them off balance and my slider had some bite to it," Ross said.

Geren said he's not ready to announce a role for Ross yet.

"We're just running everybody out there and letting them have success and will sort it out at the end," he said.

Arizona's Joe Saunders had another tough start, allowing five runs on six hits in five innings. He struck out four but also walked four. Saunders has given up 19 runs in 13 2-3 innings. David Winfree led the Diamondbacks with two RBIs.

"I felt good. The first two innings went pretty smooth," said Saunders, who retired the first six batters he faced. "The third inning, I had some tough things — a couple broken-bat hits, a couple walks. There was only on hard-hit ball in that inning. Got through that then made on bad pitch to Kouzmanoff (to lead off the fourth). Other than that, I threw the ball pretty well."

Saunders has given up 19 runs in 13 2-3 innings this spring.

NOTES: The Athletics announced RHP Trevor Cahill will be their opening day starter. ... The Diamondbacks signed RHP Kip Wells to a minor league contract. The 33-year-old has not played in the majors since 2009. ... Arizona LHP Mike Hampton was not with the team due to personal matter.