SAN FRANCISCO -- The San Francisco Giants' latest last at-bat win came at a serious price for the defending World Series champs.

Second baseman Freddy Sanchez dislocated his shoulder in the Giants' 3-2 win over the Cincinnati Reds on Friday night and will undergo further tests to determine the severity of the injury and how long he'll be out.

With catcher Buster Posey already out for the season and Pablo Sandoval on the disabled list, the loss of Sanchez counts as a major blow.

"We have to keep fighting and moving forward," said Andres Torres, who scored the winning run on pinch-hitter Nate Schierholtz's two-out single in the ninth. "That's how we did it last year, too. Freddy's a big part of us but we have to move on."

Sanchez made a backhand grab of Brandon Phillips' sharp grounder up the middle in the fifth but used his right hand to brace himself as he slid on the edge of the outfield grass. Sanchez, who underwent surgery on his left shoulder in December, sat on his knees and flicked the ball away with his glove hand as manager Bruce Bochy and assistant athletic trainer Mark Gruesbeck rushed out from the dugout.

Sanchez was later helped up and walked off the field but with his right arm held up by Gruesbeck. Bochy said Sanchez will undergo an MRI test soon.

"I can't tell you how long or how serious (it is)," Bochy said. "That's a lot, what we're taking right now. They'll keep grinding and moving forward. There's not much else you can do. We feel horrible for Freddy, a great player we'll certainly miss, but we'll move on."

News of Sanchez's injury put a downer on what was an otherwise feel-good night for San Francisco, tied Kansas City for most walkoff wins in the majors this season.

Torres, who entered as a pinch hitter in the seventh, started the ninth with a walk against Jose Arredondo (0-1). After an intentional walk to Miguel Tejada, Bill Bray came on to strike out rookie Brandon Crawford. Manager Dusty Baker then brought in Logan Ondrusek, who walked Cody Ross before Schierholtz hit for Brian Wilson (5-1).

"Walks late in the game will certainly haunt you," Reds manager Dusty Baker said. "That was a tough loss. We have had quite a few of those."

With his team slumping at the plate, Bochy juggled his lineup and moved Ross into the cleanup spot while dropping Aubrey Huff to the No. 6 slot.

The changes provided an early spark and San Francisco kept it close until Schierholtz came up with his clutch hit.

"They don't make excuses," Bochy said. "It's somebody different every day it seems like. They don't dwell on what's happened."

San Francisco, held to five hits or fewer in four of its previous six games, had five in the first three innings against Travis Wood.

Tejada hit a ground-rule double in the first and scored when Ross lined a single to left. Ross was thrown out at second on the play but after Tejada crossed the plate.

Cincinnati scored in the fourth and fifth to take the lead. Scott Rolen started the fourth with a triple off Ryan Vogelsong and scored on Ryan Hanigan's single. Chris Heisey drove in Phillips with a grounder in the fifth.

That ended Vogelsong's six-game streak of allowing one run or less. The right-hander, who was the first Giants pitcher to have such a streak since Matt Cain in 2006, left after six innings with six strikeouts and three walks.

The fifth was a rough inning all around for San Francisco.

Tejada tied it with a two-out double in the fifth and San Francisco had runners in scoring position in the sixth and eighth but failed to score.

Wood, who allowed eight runs and a career-high five walks last Sunday, was crisper in his first career start against the Giants. The left-hander gave up 10 hits and walked three over eight innings in his sixth no-decision of the season.

Wilson struck out one and allowed a hit in the ninth inning while picking up the win.

Game notes
San Francisco LHP Barry Zito will make his second rehab start Saturday against Class-A Modesto, and the team is hoping he can throw around 100 pitches. ... 3B Pablo Sandoval, expected to come off the disabled list and rejoin the Giants next week in Arizona, had two hits and two RBIs for Triple-A Fresno. ... Reds LHP Aroldis Chapman (shoulder inflammation) allowed two earned runs in 1 2/3 innings in a rehab start for Triple-A Louisville. ... Reds RHP Homer Bailey (sprained right shoulder) will begin a minor league rehab assignment on Saturday.