CHICAGO - Chicago White Sox closer Bobby Jenks underwent an MRI and a CT scan on Saturday to determine the cause of soreness below his left shoulder in his upper back. | White Sox top A's | MLB page

The tests came back negative, and the right-handed Jenks hopes to be available beginning Tuesday when the White Sox open a series in Kansas City.

Jenks, who is 2-0 with a 1.95 ERA and 18 saves in 21 opportunities, has not pitched since Sunday.

"He feels a lot better today than yesterday," White Sox manager Ozzie Guillen said.

Jenks saved 40 games a year ago, 41 in 2006 and was 4-for-5 in saves during the 2005 season when the White Sox won the World Series. Last season, he tied a major league record by retiring 41 straight batters.