Alex Gonzalez will immediately take over the shortstop duties for the team after Rich Aurilia also got injured.
Aurilia was injured while getting out of a car, hurting his ankle. He is expected to miss a week.
Sean Burroughs also went down with an injury after sliding into second base Wednesday night and was scheduled to have an MRI late Thursday in San Diego.
"That's three infielders in three days," disturbed manager Bruce Bochy said.
Gonzalez, who will join the club in San Francisco tomorrow, has appeared in 72 games in 2004, hitting a combined .229 (60-for-262) with seven home runs and 24 RBIs with the Chicago Cubs and Expos.
Gonzalez, who spent time on the disabled list with a broken right wrist, appeared in 37 games with the Cubs where he hit .217 (28-for-129) with three home runs and eight RBIs prior to being traded to the Expos in a four-team deal at the July 31 deadline.
A veteran of 11 Major League seasons with the Toronto Blue Jays (1994-1999), Cubs (2002-2004) and Expos (2004), the 31-year-old Gonzalez is a career .242 (1,107-for-4,569) hitter with 253 doubles, 128 home runs and 494 RBIs. A native of Miami, Gonzalez hit a career-best 20 home runs last season including three game-winning extra-inning homers. He also hit a solo homer off Mike Hampton in the Cubs' NL Division Series-clinching Game Five win at Atlanta. In 2003, Gonzalez led all National League shortstops with a .984 fielding percentage (10 E/625 TC).
Marty McLeary was recalled from Triple-A Portland on Aug. 22 and appeared in three games for the Padres, going 0-0 with a 14.73 ERA (6 ER/3.2 IP) before being optioned to the same Portland club on Aug. 31. The 29-year-old McLeary appeared in 44 games (seven starts) with the Beavers, going 5-4 with 13 saves and a 2.99 ERA (28 ER/84.1 IP).
Originally selected by the Boston Red Sox in the 10th round of the 1997 First-Year Player Draft, McLeary was obtained by the Padres from the Florida Marlins in exchange for right-handed pitcher Bryan Gaal on April 8, 2004. Over parts of eight minor league seasons, McLeary has a career record of 34-45 with a 4.06 ERA (280 ER/625.2 IP) in 293 games (54 starts).