Valentin pulled hamstring while running bases
The move was made retroactive to Monday.
Valentin aggravated the injury running the bases in Sunday's 5-0 victory at Tampa Bay. He is batting .271 with four doubles, three home runs and eight RBI in 10 games.
Juan Uribe is expected to play shortstop while Valentin is out.
White Sox designated hitter Frank Thomas was also sidelined with a sore hamstring. He left Sunday's game in the fifth inning after injuring his rigth hamstring while running to second base, but no update on his status was yet available.
To replace Valentin on the roster, the White Sox purchased the contract of infielder Kelly Dransfeldt from their Triple-A farm club at Charlotte.
Dransfeldt was batting .265 (9-34) one home run and four RBI in 12 games at Charlotte. He was a non-roster invitee to spring training and hit .429 (18-43) in 20 exhibition games. Dransfeldt played in 36 big league games with the Rangers from 1999-2001, batting .159 in 82 at-bats with a homer and seven RBIs.
The White Sox also announced the resignation of Rob Gallas, who had been the club's senior vice president of marketing and broadcasting for nearly 15 years.
"It was a very difficult decision, but it's time for a change and new challenges," Gallas said. "I need to take a step back, and this seemed like the time to do it. The 2004 marketing plan is set and everything is in place for the season."
Copyright 2004 by The Associated Press