SAN FRANCISCO -- After spending two of his off-days in Houston working on catching drills, Buster Posey checked off the final box in preparation for his Saturday start behind the plate before Friday's game against the Red Sox.

Posey, along with backup catcher Eli Whiteside, practiced taking pop flies, as well as relay throws, before batting practice Friday.

Giants manager Bruce Bochy recently said that Posey, who has started at catcher once in 21 games, would begin seeing more time behind the plate -- perhaps as often as once through the pitching rotation.

As for Friday's pregame drills, Bochy said it was nothing more than a little fine-tuning.

"He got a little bit of early work, which we do with these guys when they haven't played a position a lot," Bochy said. "In this ballpark, popups can be pretty tough to handle, so we were just getting some work."

Bumgarner tabbed to face Red Sox

SAN FRANCISCO -- Giants manager Bruce Bochy confirmed after Friday's game that top pitching prospect Madison Bumgarner will start Saturday's game against the Red Sox.

Bumgarner, 20, was originally slated to start Friday night at Triple-A Fresno, but was scratched in case the Giants needed a starter for Saturday. With right-hander Joe Martinez having warmed up in the bullpen in the top of the third inning -- and not having started a game since June 15 -- the Giants now are in need of one.

In 14 starts this season at Fresno, Bumgarner is 7-1 with a 3.16 ERA. He pitched in four Major League games last season as a September callup, starting once against the Padres, allowing two runs on five hits in 5 1/3 innings.

Saturday's task against the Red Sox figures to be a bit tougher, but Bochy thinks Bumgarner is up for it.

"You're going to face a Major League team," Bochy said. "Sure, they're a great team, but he's fresh."

Giants bullpen getting plenty of work

SAN FRANCISCO -- With Giants starting pitchers posting only one quality start in the past four games, the San Francisco bullpen has lately logged the majority of the innings.

Giants relievers have worked 16 2/3 of the Giants' last 34 innings, including 5 1/3 scoreless innings Thursday in Houston, allowing only four runs in that stretch.

Three -- right-handers Denny Bautista and Guillermo Mota and lefty Dan Runzler - have pitched the past two days, but Runzler faced only one batter Wednesday.

Bochy said Bautista is the one reliever he'd like to stay away from.

"Hopefully [Giants starter Jonathan] Sanchez goes out there and gives us a good effort, [and goes] somewhat deep in the game," Bochy said.

Giants to collect gloves for kids

SAN FRANCISCO -- Giants fans with new or gently used gloves can help support the Junior Giants on Saturday as part of the Junior Giants Glove Drive at AT&T Park.

Junior Giants is a youth baseball organization with about 16,000 players in California, Nevada and Oregon, but of that number, more than 6,200 players do not have gloves.

The drive, presented by Bank of America, greatly enhances the quality of play for the Junior Giants, 75 percent of whom would not be able to play baseball without the program.

After Saturday's game, supporters of the Giants Community Fund also can take part in a postgame live action, featuring memorabilia, with Giants players and wives.

Those who donate gloves, or give $10 or more, will receive a commemorative "Pandoval" pin feature Giants third baseman Pablo Sandoval.

Worth noting

Giants infielder/outfielder Mark DeRosa told KNBR that surgery on his left wrist is scheduled for July 1. ... Giants manager Bruce Bochy said right-hander Todd Wellemeyer, on the 15-day disabled list since June 11 with a quad strain, still is sore and his return date is in the area of 10 days to two weeks. ... A reminder that the Giants will retire Monte Irvin's No. 20 on Saturday in a pregame ceremony prior to the club's 4:10 p.m. PT game against Boston. The ceremony will begin at 3:30 p.m. and will include fellow Hall of Famers Willie Mays, Willie McCovey, Juan Marichal, Gaylord Perry and Orlando Cepeda.