SAN FRANCISCO -- The San Diego Padres found the bullpen help they were seeking, acquiring right-hander Scott Williamson on Saturday from the Chicago Cubs in exchange for two minor league pitchers.

The Cubs received Class-A pitchers Fabian Jimenez and Joel Santo in the deal. The Padres are still looking for a third baseman before the trading deadline.

"For the last couple of years our bullpen has been a large part of the reason we've been able to not only win the division last year but stay in contention," Padres general manager Kevin Towers said Saturday before the Padres played the San Francisco Giants. "I don't think you can ever have enough arms. This guy's been a closer before, been an All-Star. It just adds another arm to the mix in the late innings."

The 30-year-old Williamson is scheduled to join the Padres on Monday in Los Angeles for the opener of a three-game series with the Dodgers. He went 2-3 this season for the Cubs with a 5.08 ERA in 31 relief appearances, striking out 32 batters -- including at least one in 22 of his outings.

Towers said the trade was in the works for about a week as the Padres tried to add some depth to their taxed bullpen.

"He's somebody we've liked for some time," Towers said. "And we didn't have to take away from our big club. That was probably one of the keys to it. We were able to move two young pitchers. It seems like everybody's looking for relief help right now. So to be able to add an experienced bullpen arm at this time when everybody else is out looking for it, we think is a real shot in the arm for us."

Williamson, a power pitcher with a lively fastball, will likely be used in middle relief as a one-inning guy by manager Bruce Bochy, Towers said. He doesn't expect to look further to bolster the bullpen, turning his focus to third base.

The Padres will need to make a roster move before Monday's game, but Towers expects the team to keep 12 pitchers. That's if outfielder Brian Giles' tight right hamstring doesn't become a lengthy injury. He missed his second straight game Saturday night.

"He's feeling better," Towers said, noting he doesn't expect Giles to need a stint on the disabled list.

Both Jimenez and Santo were pitching for Class-A Fort Wayne. Angulo is 5-7 with a 4.43 ERA. Santo is 5-6 with a 5.51 ERA.

Chicago has struggled all season and is currently in fifth place in the National League Central with a 37-59 record, 17½ games behind the first-place St. Louis Cardinals.

San Diego is in first place in the NL West but has lost two straight to the San Francisco Giants to see its lead cut to just ½ game entering Saturday's action.

Williamson played the first four-plus seasons of his career in Cincinnati before being traded to Boston in 2003. He joined the Cubs in 2005. Williamson's career ERA is just 3.22, but that number has been over five in each of his seasons with Chicago.