Along with recalling catcher Steve Holm and right-handed pitcher Brad Hennessey from Triple-A Fresno, the Giants also purchased the contract of infielder Scott McClain from the Grizzlies. To make room for McClain on the 40-man roster, San Francisco released catcher Guillermo Rodriguez.
In addition, the Giants activated left-handed pitcher Jonathan Sanchez from the 15-day disabled list. Sanchez, who already established a career-high eight victories this season, started Monday's game against the Rockies after being sidelined since Aug. 16 with a left shoulder sprain.
There have been recent concerns about the durability of the starting rotation, but manager Bruce Bochy said Hennessey will be used out of the bullpen, which has also been worked heavily of late. Hennessey began the year on the Giants' Opening Day roster but struggled, forging a 12.94 ERA in 11 outings.
The Giants' first-round selection in the 2001 First-Year Player Draft, Hennessey posted a 7-10 record with a 4.83 ERA in 21 starts for Fresno this season.
"He's starting to throw the ball better; he's stretched out," Bochy said. "It's something we want to look at, especially if you look at that series in Cincinnati. They hit our bullpen pretty good all three games. We feel like he can give us three or four innings [an outing]."
The Giants were excited about adding McClain's bat to the lineup after having a great season with Fresno. McClain, 36, batted .300 with a team-high 29 home runs and 108 RBIs in 134 games with the Grizzlies.
"Mac had another great year down there in Fresno," Bochy said. "He's certainly earned [the callup]."
Holm will be making his third stint with San Francisco this season. The 28-year-old batted .256 with one home run, eight doubles and five RBIs in 45 games for the Giants this year. He made 19 starts and threw out two of 23 attempted base stealers.
Rodriguez, the one roster casualty, batted .266 with two home runs and seven RBIs in 33 games for Fresno this season. Rodriguez, 30, reached the Majors for the first time last season, batting .253 in 39 games with the Giants.
Jeff Birnbaum is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.