SAN FRANCISCO -- Time is running out for Fred Lewis' sore left side to be healed by Opening Day, increasing the existing likelihood that the outfielder will begin the season on the 15-day disabled list.

Lewis, who initially reported feeling discomfort in his ribs last week, hit off a batting tee and ran Thursday. But he realizes that he needs much more activity than that to be game-ready.

"I need more at-bats right now, because timing-wise, sitting around not doing anything is not going to flip the switch," Lewis said.

Manager Bruce Bochy acknowledged that Lewis, 29, might have to be shelved when the Giants set their season-opening roster.

"Is there a possibility he could go on the DL? Sure," Bochy said. "We're not going to push him and get him out there and have any setbacks. He's doing better and I know there's not much time."

Lewis, who was competing for a reserve outfield spot, owns a .222 batting average in 14 exhibition games. But his extra-base prowess -- three homers and one triple -- has swelled his slugging percentage to .528.

"I was seeing the ball perfectly and all the way up until then I had done all that hard work," Lewis said. "Then all of a sudden it seemed like it faded away. Now I have to work my way from the bottom to the top."

If Lewis indeed starts the season on the disabled list, each of the other contenders for jobs as extra outfielders -- John Bowker, Andres Torres and Eugenio Velez -- likely would make the Opening Day roster.

Zito shrugs off rough outing vs. A's

SAN FRANCISCO -- There was a bright side to Barry Zito's performance Thursday night against the Oakland A's.

Now he knows what to work on before he faces the Houston Astros next Tuesday in his first regular-season start.

Zito's pitching mechanics went awry against the A's, who amassed five runs and seven hits in his three innings during the Giants' 9-0 exhibition loss at AT&T Park.

Zito recorded a 6.35 ERA in six spring appearances, though he built endurance by pitching into the seventh and sixth innings in his previous two games. That afforded him some perspective as he summarized his outing.

"I felt good all spring, so throw it away," he said.

Zito won't discard the entire experience, however.

"A couple of things I'll clean up before my next start," he said.

One item on Zito's list will be his slider. He threw one to Kurt Suzuki that he described as "flat." It was last seen disappearing over the left-field barrier for a two-run homer in the first inning.

Nor did Zito's delivery seem right to him.

"My timing was off," he said.

Giants manager Bruce Bochy noticed the flaw.

"He got a little quick out there," Bochy said.

Zito was backed by a contingent that's expected to be the Giants' Opening Day lineup. Asked if this was indeed his starting eight position players, Bochy said, "It could be. I'm not saying it is, but it's pretty close. It's real close, I'll say that."

Bochy added that right field remained the only possible discrepancy. Nate Schierholtz, the projected starter at that spot, started Thursday, though Bochy said that John Bowker still has a chance to claim the job.

"Johnny's been swinging the bat well," Bochy said of Bowker, who's hitting .310 with a team-high five home runs and 20 RBIs. "It's fair to say that Nate [.233] hasn't found his groove yet, but he's going to be on the club. We'll be using all those guys. Whoever starts in right field, the other guy's not going to be forgotten."

Giants get pitching prospect from Texas

SAN FRANCISCO -- Instead of simply losing left-hander Ben Snyder in last December's Rule 5 Draft, the Giants received another pitcher in return.

The Giants traded Snyder to the Texas Rangers on Thursday for Minor League left-hander Edwin Escobar, completing a sequence of player moves.

The Baltimore Orioles made Snyder their Rule 5 selection after he compiled a 33-19 record with a 2.98 ERA in four Minor League seasons with the Giants. The Orioles then sent him to Texas as the player to be named later in a trade that moved right-hander Chris Ray to the Rangers and brought right-hander Kevin Millwood to Baltimore.

Under the conditions of the Rule 5 Draft, the Rangers had to keep Snyder on their Opening Day roster or offer him back to the Giants for $25,000. Texas could not send him to the Minors without making a deal with the Giants once he cleared waivers. As is sometimes the case with Rule 5 selectees, the Rangers chose that option.

Escobar, who has been assigned to the Giants' Minor League camp, went 2-5 with a 5.00 ERA with the Rangers' Rookie-level Arizona League squad last year. He struck out 48 and walked 16.