The 35-year-old returned to San Francisco's lineup Saturday, and he went 0-for-4 with three strikeouts against the Red Sox to drop his average to .236.
Aurilia has flown back to San Francisco to confer with team doctors. He will undergo a magnetic resonance imaging scan Tuesday to determine the severity of his injury.
"They're trying to find out what exactly the issue is," Bochy said.
The Giants made the move retroactive to Sunday and called up infielder Luis Figueroa from Triple-A Fresno to take Aurilia's spot on the roster. Figueroa was hitting .310 with a home run and 26 RBIs with Fresno.
Ryan Klesko missed the first two games during the Boston series with tightness in his lower back and left hip, but Bochy said Klesko has recovered and is good to go. Bochy said he can still turn to Mark Sweeney to back up Klesko at first.
Bochy will use Figueroa as a utility infielder to spell Ray Durham at second base and Omar Vizquel at shortstop.
"We felt like we needed some infield help, so he'll help us there," Bochy said.
Under the knife:
Giants head athletic trainer Dave Groeschner also announced that backup catcher Eliezer Alfonzo will undergo surgery Tuesday to repair the torn posterior cruciate ligament in his left knee.
Dr. Tim Kremchek will perform an arthroscopic procedure to repair Alfonzo's knee Tuesday in Cincinnati.
"We'd like to take care of it, and that's what Eliezer wants to do," Groeschner said. "It sounds like it's a wise thing to get this done right now."
Alfonzo, who was transferred to the 60-day DL to make 40-man roster room for Figueroa, suffered the injury in San Francisco's 5-3 loss to the Athletics on June 8, when A's pinch-runner Donnie Murphy whacked Alfonzo's knee while sliding into home plate.
Alfonzo had considered rehabilitating his knee without any surgery, but he decided against it because it would have taken at least two months anyway before he would have been able to play again. Groeschner said the surgery will cause Alfonzo to miss about six to eight weeks of action.
"The whole reason to do it," Groeschner said, "is just so that six weeks into it, when he's trying to go back to baseball and catching, we don't have an issue of a meniscus tear and soreness, and now we need to scope this."
With the Giants rolling into the city where Hank Aaron played 14 of his 23 big-league seasons and hit his 755th home run, talk of Barry Bonds' pursuit of Aaron's home run record naturally dominated Bochy's pregame media session.
Bonds entered Monday evening's contest seven home runs shy of tying Aaron's mark. The slugger hit No. 748 against the Red Sox on Sunday.
"I think [the home run chase] is getting all the credit it deserves," Bochy said. "You're talking about him passing the greatest home run hitter of all time, and now you're becoming the greatest home run hitter. I don't think you can make too big a deal out of that, and it's well deserved on his part."
Bonds is hitting .287 with 14 home runs and 31 RBIs. The slugger has done well at Miller Park throughout his career, sporting a .373 batting average with six home runs in 51 at-bats in the ballpark.
Bonds slugged 11 home runs in his first 76 at-bats but cooled off after that, hitting just three in his next 91. But Bochy pointed out Bonds still ranks first in the Majors with 67 walks, 12 more than the Indians' Travis Hafner in second place.
"Questions keep coming up, 'Well, can Barry still do it?'" Bochy said. "Obviously, teams on the other side think he can."
The Brewers traditionally have pitched to Bonds, perhaps more than other teams. The slugger entered the series a career .370 hitter against Milwaukee while averaging a home run every 7.86 at-bats, by far his best rate against any National League opponent. In 2004, Brewers pitchers served up career homers Nos. 660 and 661, allowing Bonds to tie and pass his godfather, Willie Mays, for third on the all-time list.
The Brewers are tied for second in the Majors, having issued just nine intentional walks entering Monday's contest.
"Every time we walk him, he ends up scoring anyway, so it doesn't make any sense to walk him," Brewers manager Ned Yost said. "A walk is like a home run. You look at his batting average, and even if he's hitting .400, he's still making six outs [every 10 at-bats]. If we walk him every time, he's not making any outs.
"You play the odds. If it's a spot where he absolutely has an opportunity to kill you, you take your chances and walk him."
Bochy didn't see too much of the Brewers' prized pitching prospect Yovani Gallardo in Spring Training, but what he did see left him impressed.
Gallardo, who made his Major League debut Monday evening, pitched two shutout innings against the Giants in a 21-2 Brewers victory on March 2. The right-hander struck out two batters, including Bonds swinging on four pitches.
"He's got a good fastball, curveball, slider, change," Bochy said. "He's got good stuff."
Giants rookie Tim Lincecum has struggled in the month of June, going 0-1 with a 9.82 ERA in his three starts so far. The young right-hander will try to turn things around Tuesday night against Ben Sheets and the Brewers.