SAN FRANCISCO -- Seeking bullpen depth, the Giants agreed to terms on a Minor League contract with right-hander Brad Penny on Friday.

Penny, released last week by the Softbank Hawks of the Japanese Pacific League after 12 seasons in the Majors, will report to the Giants' extended spring training camp Monday to work himself into pitching shape. He made only one start in Japan.

Penny has started in all but four of his 319 appearances in the Majors. But the Giants have been seeking reinforcements for their relief corps, particularly with right-hander Guillermo Mota serving a 100-game suspension for use of a performance-enhancing substance. Penny's experience as a starter would enable him to transition smoothly into the multiple-inning long-relief role Mota occupied.

Penny, who turns 34 next Thursday, built a 119-99 record with six big league teams, including a highly successful stint with the Giants in September 2009. He was 4-1 with a 2.59 ERA in six starts. San Francisco attempted to retain him, but he signed with St. Louis.

Last year, Penny finished 11-11 with a 5.30 ERA in 31 starts for Detroit.

Giants give Posey a night of rest vs. A's

SAN FRANCISCO -- Choosing long-term benefits over short-term gain, Giants manager Bruce Bochy stuck to his plan to keep Buster Posey out of the lineup for Friday's Interleague series opener against the Oakland A's.

Posey wasn't expected to catch, since Hector Sanchez typically handles that duty when Barry Zito starts. But Bochy briefly considered keeping Posey's bat in the lineup by starting him at first base. Posey went 5-for-8 in the two-game series against St. Louis, lifting his batting average from .280 to .302.

"It's not easy to take your cleanup hitter out of the lineup," Bochy said. "But you hear me say this all the time: diminishing returns."

In other words, Bochy wants to avoid wearing out Posey physically. Nearly a year removed from sustaining multiple left leg injuries, Posey appeared in 34 of San Francisco's first 39 games, starting 32 -- 25 at catcher and seven at first base.

Center fielder Angel Pagan replaced Posey in the cleanup spot. Pagan last batted fourth on June 13, 2011, against Pittsburgh.

Arias returns to action after injury

SAN FRANCISCO -- Joaquin Arias returned to the Giants' lineup Friday at third base, having recovered sufficiently from the bruised left forearm that forced him to miss Wednesday's and Thursday's games against St. Louis.

Arias was injured when he was hit by a pitch from Colorado's Jeremy Guthrie on Tuesday. X-rays revealed no fracture.

Giants manager Bruce Bochy had Arias in the original lineup but didn't finalize the utility man's playing status until watching him hit in batting practice.

"Is he 100 percent? No," Bochy said.

Worth noting

• A report stating that the Giants have offered a contract to 40-year-old utility man Melvin Mora to increase their infield depth is completely false, industry sources said Friday. Lider de Deportes claimed that Mora, who hit .228 in 42 games with Arizona last year, had received offers from the Giants and Cincinnati Reds. But Ryan Theriot will become eligible to be reinstated from the disabled list next Thursday, and the Giants still haven't given up on Freddy Sanchez returning. Manager Bruce Bochy said that Sanchez, whose recovery from a dislocated right shoulder was interrupted by back discomfort, is improving and could resume playing extended spring training games in Arizona as early as this weekend.

• For those same reasons, the sources said that the Giants have no interest in second baseman Orlando Hudson, whom San Diego released Thursday. Hudson, who has played for four teams in five years (the D-backs, Dodgers and Twins besides the Padres), was batting .211 in 35 games for San Diego.

• In a pregame ceremony, Bochy presented San Francisco mayor Ed Lee an orange jersey bearing No. 75 and signed by the entire team to observe the 75th anniversary of the opening of the Golden Gate Bridge. The Giants also wore commemorative patches on their jerseys to celebrate the occasion.