Barry Zito is back to walking batters with regularity. The offense is suddenly struggling, and Pablo Sandoval has an injured hand that could sideline the Giants slugger.

San Francisco's 2012 season is starting to feel a lot like 2011 all over again.

Zito tied a career-high with seven walks and Sandoval left after the sixth inning with an injured left hand and wrist, highlighting a 3-2 loss in 10 innings to the Miami Marlins on Wednesday night.

"We just have to keep our heads up and pick up some slack around here," said Zito, who lasted only 3 2-3 innings.

The Giants rallied from two runs down against struggling Marlins closer Heath Bell to force extra innings.

Then Giancarlo Stanton homered off Santiago Casilla (0-1) in the 10th to bail out Bell. Stanton's third long ball of the season followed a wild ninth that saw struggling Bell blow his fourth save in seven chances and raise even more doubt about the back-end of Miami's bullpen.

Carlos Zambrano pitched seven scoreless innings, and Steve Cishek (3-0) relieved Bell for the final six outs to give Miami its second straight win in San Francisco.

Even worse for San Francisco, Sandoval left after grounding out in the sixth with a left hand and wrist injury. Manager Bruce Bochy said it was unclear how the third baseman hurt his hand.

Sandoval, who missed about a quarter of the season last summer after surgery on his right wrist, is batting .316 with five home runs and 15 RBIs this year. No immediate X-rays were taken, a team spokesman said, and Sandoval will be reevaluated Thursday.

"I have a lot of concern," Bochy said. "You just hope for the best."

A series of mistakes by Miami's new high-priced closer almost turned into another loss.

Brandon Belt lined a double to left leading off the bottom of the ninth. Joaquin Arias singled home Belt, and Buster Posey followed with another hit to chase Bell.

After Cishek struck out pinch-hitter Brett Pill, Gregor Blanco bunted down the first-base line. Gaby Sanchez fielded the ball cleanly but had no play, allowing Arias to score the tying run.

Angel Pagan grounded into a fielder's choice and Melky Cabrera had an infield single to short that loaded the bases. Ryan Theriot, batting in Sandoval's place, hit weak groundout to second sent the game to extra innings, where Miami backed its struggling closer.

The big man at the back end of the bullpen has looked nothing like his old self.

The 34-year-old Bell had 40-plus saves each of the past three seasons with the San Diego Padres, including 43 in 48 chances last year with a 2.44 ERA. He leads the majors with 134 saves over the past three-plus seasons. Bell's ERA so far this season is 11.74.

"In this county, you're only famous when you (mess) up," Marlins manager Ozzie Guillen said of Bell. "They forget everything when you're good."

In contrast, Zito reverted back to his wild ways after a surprisingly strong April.

The slow-throwing left-hander's curveballs danced anywhere but in the strike zone. He threw 60 pitches in the first two innings — finishing with 91 total, only 50 for strikes — and his defense did him no favors.

With one out and the bases loaded in the first, Brandon Crawford mishandled a grounder to short by Omar Infante. Crawford threw out the runner at second, but Joaquin Arias' relay to first was too late, allowing Emilio Bonifacio to score.

Zito walked two more in the second and again nearly worked out of a jam. Instead, Arias bungled a grounder by Bonifacio off his glove for an error, and Gaby Sanchez scored to give Miami a 2-0 lead.

The Marlins had lost eight of nine before traveling to the West Coast. A new month has been kinder so far to rebranded Miami.

Zambrano quieted San Francisco's hitters, not allowing a single hard-hit ball in spacious AT&T Park. He allowed five hits and struck out five in seven scoreless innings.

But he had to endure Bell's blow save that cost him the win.

"I feel that I'm a new Carlos Zambrano," the right-hander said. "The old Carlos Zambrano would be throwing his chair and screaming at his teammate."

NOTES: Giants 2B Freddy Sanchez, recovering from another setback on his surgically repaired right shoulder, took infield practice and played long toss with OF Aubrey Huff before the game. Huff is on the 15-day disabled list with what the team has called an anxiety disorder. ... Marlins LF Logan Morrison had the day off with a lefty starter on the mound, giving him a chance to rest his nagging right knee. Austin Kearns started in his place.