SAN FRANCISCO -- Of all the roster moves the Giants have made lately, one of the most intriguing transactions was one that they didn't make.

Needing 40-man roster room for left-hander Eric Surkamp, who started Saturday, the Giants easily could have transferred Barry Zito from the 15-day disabled list to the 60-day DL, which would have essentially ended his season. Instead, the Giants designated Double-A left-hander Clayton Tanner for assignment, sending the message that they still deemed Zito, who's recovering from a right ankle injury, potentially useful.

Manager Bruce Bochy clearly stated that this was indeed the case.

"He could be ready in a couple of weeks," Bochy said. "That's what we may need, as banged up as we've been getting."

Zito, who threw off a bullpen mound Friday at the Giants' training complex in Arizona and Sunday at AT&T Park, said that he feels good "stuff-wise" but noted that no timetable has been set for his return.

Asked if he had contemplated long-range issues, such as his future with the Giants, Zito said, "My mind has gone to those places, sure. But what can I control? I control what I do today and give my best effort today."

Citing the importance of maintaining "integrity" of effort, he added, "Good things will come when you do that consistently."

The Giants still owe Zito $19 million next year and $20 million in 2013 under terms of his seven-year, $126 million contract. Should they decline to pick up the $18 million club option for 2014, Zito would be due a $7 million buyout.

Outlook getting bleak for lefty Sanchez's return

SAN FRANCISCO -- Manager Bruce Bochy hinted Sunday that Jonathan Sanchez, who began the season as the Giants' No. 2 starter, could be sidelined for the rest of the season with his sprained left ankle.

Bochy said that Sanchez hasn't tried throwing since Aug. 19 at Houston, when hope still existed that the left-hander might be able to start the next day. But Sanchez's ankle still felt unstable during that throwing session.

Asked if Sanchez could be out for the season, Bochy said, "I don't think so. But the longer this keeps going without him throwing, you start getting concerned."

Bochy even suggested that Sanchez isn't much farther along in his recovery than catcher Buster Posey, who's sidelined for the season as he recovers from a fractured left leg.

"The way it's going, it'll be a close call between him and Buster," Bochy said. "Those ankle sprains are so hard to read. There are times when they say that you're better off breaking the bone."

Sanchez, who's 4-7 with a 4.26 ERA in 19 starts, has been replaced in the rotation by rookie left-hander Eric Surkamp, who allowed one run in six innings Saturday night in his Major League debut.

Surkamp, Runzler sent out to open roster spots

SAN FRANCISCO -- Given Thursday's expansion of roster limits to 40 players, the Giants' personnel moves Sunday amounted to juggling, not demoting.

As anticipated, San Francisco activated outfielder Andres Torres (bruised right leg) and right-hander Sergio Romo (elbow inflammation) from the 15-day disabled list. The Giants cleared roster room for them by optioning left-handers Eric Surkamp to high-Class A San Jose and Dan Runzler to Triple-A Fresno.

Manager Bruce Bochy said that both Surkamp and Runzler will officially rejoin the Giants when they're eligible after Thursday. Surkamp, who pitched impressively in his Major League debut against Houston on Saturday, already has received his next starting assignment -- Sept. 6 at San Diego. Given Thursday's scheduled off-day, that will be the next day the Giants need a fifth starter. Surkamp, who limited the Astros to one run in six innings, will start for San Jose on Thursday to stay sharp.

Worth noting

• Pablo Sandoval's sore left shoulder, which prevents him from batting right-handed, has begun to improve. Bochy knows this, because he saw Sandoval arrive at AT&T Park early Sunday to take some right-handed practice swings. "I don't think he likes coming out when a left-hander comes in," said Bochy, who pinch-hit Orlando Cabrera for the switch-hitting Sandoval when Houston inserted lefty Wesley Wright in Saturday's eighth inning.

• Bochy said that right-hander Brian Wilson, who's recovering from a strained right elbow, threw for about 10 or 11 minutes Sunday. Wilson is likely to rest Monday and be re-evaluated.

• Jeff Keppinger's walk-off single Saturday and game-winning, two-run double in Friday's fifth inning didn't go unnoticed. According to the Elias Sports Bureau, it marked the first time since 1977 that a player put together that combination in a single series against a team he played for earlier in the season.