SAN FRANCISCO – Terry Francona has learned a lot about his team’s perseverance this season. As the Red Sox have lost star player after star player to injury along the way, they have ground out wins with others filling the void.

This time, it was Scott Atchison — with a big assist from Mike Cameron’s bat and glove and the rest of the bullpen — on a day Boston was dealt a double whammy.

Second baseman Dustin Pedroia went on the disabled list with a broken left foot, then a few hours later pitcher Clay Buchholz left his outing after only one inning with a hyperextended left knee.

Cameron hit a three-run homer, Darnell McDonald also connected, and the Red Sox beat the San Francisco Giants and their top pitching prospect 4-2 Saturday night.

“We’ve played with so much better personality the last month and a half,” Francona said. “It’s a good feeling. This team’s forming its own personality.”

Atchison (1-1) tossed 2 1/3 innings for the win against his former team after Buchholz got hurt while running the bases. The Red Sox used seven relievers to pull this one out.

“That was the bullpen’s win today,” said Buchholz, who hopes to make his next turn even if it’s pushed back because of two upcoming days off. “They did what they had to do on 30 seconds’ notice. (Atchison) started it.”

The Giants called up Madison Bumgarner (0-1) from Triple-A Fresno to make his 2010 debut and second career start. He struck out five and allowed four runs and five hits in seven innings, but he had to throw a lot of pitches to get through Boston’s dangerous lineup. He didn’t get much help from the offense, either.

Buster Posey drove in both Giants runs, but that wasn’t enough as the Red Sox rebounded to even the series following a 5-4 loss Friday night.

Along with his first home run in a season that featured more than a month on the disabled list with an abdominal strain, Cameron made a stumbling catch at the wall on Pablo Sandoval’s fly ball to end the eighth.

While Francona ranked the defensive play ahead of the long-awaited home run, Cameron was happier with the homer.

“That’s big,” Cameron said. “I’ve come close. I think I got snakebit off the walls in Fenway a couple times. I knew I hit it good, but I hit it good in Colorado and it didn’t go out. I was starting to doubt I still had a little pop in my bat.”

Jonathan Papelbon worked a 1-2-3 ninth on eight pitches for his 17th save in 20 chances.

Buchholz singled in the top of the second and was injured moments later running between first and second on Marco Scutaro’s inning-ending double play. Buchholz grabbed his left hamstring in the dugout.

In the middle of the game, the Red Sox announced they acquired infielder-outfielder Eric Patterson from Oakland for minor league pitcher Fabian Williamson.

Getting Patterson adds to Boston’s depth with Pedroia out.

 

PEDROIA WENT on the 15-day disabled list, and it’s unclear how long he might be sidelined or whether he could need surgery.

He said inserting a pin into the foot is an option to help him heal more quickly, but he’ll know more after he is examined by team doctors Monday.

“In the past I’ve healed pretty quick,” Pedroia said. “I hope I do the same this time.”

Pedroia fouled a ball off his foot during Friday night’s 5-4 loss to San Francisco and was removed from the game in the third inning after staying in to finish his plate appearance with a walk.

Francona said tests revealed a non-displaced fracture in the middle of Pedroia’s left foot despite an initial result of negative X-rays late Friday.