SAN FRANCISCO -- The Giants made a quick call to the bullpen Friday, focusing on relief pitchers as open bidding for free agents began.

Asked if the Giants made any formal offers, general manager Brian Sabean said, "We're active. We're talking to people who are definitely interested in us."

Left-hander Joe Beimel is among the relievers commanding San Francisco's attention. A source familiar with the negotiations called the Giants' pursuit of Beimel "sincere." Also, Bob Howry "may" draw interest from the Giants, as the right-hander's agent, Craig Landis, said in an e-mail.

Right-hander Juan Cruz and left-hander Jeremy Affeldt also are likely to be on the Giants' list. San Francisco needs bullpen reinforcements after a season in which its relievers tied for 14th in the National League with a 4.45 ERA and allowed the third-most home runs (62) despite pitching the fourth-fewest innings (487 1/3).

Additionally, the Giants sought to address their infield needs, as the agents for shortstop Rafael Furcal and third baseman Casey Blake confirmed being contacted by San Francisco.

"There is strong mutual interest," said Furcal's agent, Paul Kinzer, who noted that eight to 10 teams are eyeing his client. "They've been one of the more aggressive teams and have let me know they really like him."

"He's one of a number of scenarios they're processing right now," said Blake's agent, Jim McDowell. "They're like some other teams. They have some trade expectations."

Sabean acknowledged that the Giants are continuing trade talks but are concentrating more on free agents at this juncture "because that's what you can control."

Although Sabean declined to name any of the free agents the Giants are considering, it's apparent that left-hander CC Sabathia remains on the Giants' list of possible acquisitions, despite his staggering price tag. The New York Yankees reportedly offered Sabathia a six-year contract worth close to $140 million. Yet plenty of buzz persists throughout the industry that San Francisco ultimately will accelerate its efforts to land Sabathia, who would turn the Giants' respectable starting rotation into a formidable one.

Indications were that the Giants weren't in the running for the other two premier free agents, first baseman Mark Teixeira and left fielder Manny Ramirez. Scott Boras, who represents both sluggers, made minimal remarks about the Giants' involvement. "I can only say that I've communicated with the baseball people of the Giants, as we always do," Boras said.

Even free agents other than Sabathia, Teixeira and Ramirez won't be discounted. Beimel, who had a $1.925 million base salary with the Dodgers last season, and Cruz, who earned $1.9375 with the D-backs, can expect to significantly increase their annual wage.

Nor will position players come cheaply. Furcal, 27, is coming off a three-year, $39 million deal with the Dodgers, although the injuries he has endured the last two years could temper his demands. McDowell expects that Blake, who earned $6.1 million last season, during which he was traded to the Dodgers, will get the three-year contract he seeks despite being 35.

Signing Furcal likely would prompt the Giants to move Emmanuel Burriss to second base and try Kevin Frandsen at third. Acquiring Blake would make Pablo Sandoval the favorite to claim first base, with Travis Ishikawa and John Bowker providing competition. Yet the Giants would have some flexibility, given Blake's experience at first base and in the outfield.

Representatives for other free agents who could fill the Giants' needs -- including infielder Edgar Renteria and relievers Brandon Lyon and Kyle Farnsworth -- said they hadn't been contacted by San Francisco as of Friday afternoon. The Giants have plenty of time to add such players to their shopping list. Last offseason, for example, the Los Angeles Angels signed center fielder Torii Hunter with a late offer that trumped all others.

"I think other teams have gone to school on that and there will be a certain amount of that," one agent said. "What really means something is when offers start showing up."