With Padres starting catcher Ramon Hernandez out at least three weeks due to a cartilage tear in his left wrist, the Padres traded infielder J.J. Furmaniak to the Pirates for David Ross.
The Padres hold a two-game lead over Arizona in the NL West and have used Robert Fick and Phil Nevin behind the plate.
Ross, who has been playing at Indianapolis, was hitting just .211 at the Triple-A level.
Originally drafted by Los Angeles in the 7th round of the 1998 First-Year Player Draft, Ross has appeared in 158 Major League contests, batting .211 (86-for-407) with 19 doubles, 19 home runs and 50 RBI over parts of four seasons with Los Angeles (2002-04) and Pittsburgh (2005).
Furmaniak, 26, appeared in 99 games for Triple-A Portland, batting .266 (103-for-387) with 16 doubles, 14 home runs and 47 RBI. Originally selected in the 22nd round of the 2000 First-Year Player Draft, Furmaniak appeared in 633 minor league games for the Padres, batting .274 (640-for-2337) with 128 doubles, 61 homers and 309 RBI.