CHICAGO -- With the bullpen stretched thin by overuse and injury, the White Sox placed relievers J.J. Putz and Matt Thornton on the disabled list Wednesday and activated two pitchers.

"Thornton's out, Putz is out and we're going to add two guys," White Sox manager Ozzie Guillen had said after Tuesday's 7-5 win over Baltimore. "Right now I need some guys who can go out there."

Matt Thornton hasn't pitched since Aug. 17 due to a sore arm. Jerry Lai/US Presswire

The White Sox recalled right-hander Lucas Harrell from Triple-A Charlotte and reinstated lefty Erick Threets from the disabled list following a rehab assignment with the minor league club before Wednesday's game against Baltimore.

Thornton, an All-Star, hasn't pitched since giving up a

walk-off homer to Jim Thome on Aug. 17, and was placed on the DL retroactive to Aug. 18 because of inflammation in his left elbow. He is 3-4 with a 2.66 ERA and leads AL relievers with 66 strikeouts.

Putz lasted just three pitches before leaving Tuesday's game in the ninth because of right knee tendinitis. He is 6-5 with a 2.68 ERA.

Both pitchers got MRIs on Monday for their respective injuries. Thornton had some fluid dried out from his left elbow joint after reporting soreness in his forearm. Putz had inflammation in his right patella tendon.

"I feel better today than I did yesterday," Thornton said before Tuesday's game. "That's the first time in four or five days that it feels better. They put something in to help dry up the fluid. They didn't draw anything out; they tried. They injected a little something to dry it out."

After Chris Sale pitched a perfect eighth in relief of Gavin Floyd, Sergio Santos gave up two runs in the ninth and left the game with no outs and two runners on. Putz had a 3-0 count on Ty Wigginton when he departed.

With a depleted bullpen -- including Tony Pena, who was off-limits after throwing seven innings in a spot start Saturday -- Guillen went to Bobby Jenks, who threw a season-high three innings Sunday. Jenks got Wigginton to ground into a run-scoring double play and Luke Scott to fly out to end the game.