TUCSON, Ariz. (AP) _ Chicago White Sox left-hander Mark Buehrle had tests Monday to determine whether he had a broken left foot.

Buehrle, slated to be Chicago's opening-day starter, felt a pop while shagging fly balls Sunday but he didn't report to the trainer's office.

An MRI exam Monday was inconclusive, and the White Sox scheduled a CT scan to determine the extent of the injury.

After going home and taking a nap Sunday, Buehrle awoke with soreness in his foot and was barely able to walk, according to Chicago head trainer Herm Schneider.

He did not have a limp when he arrived at training camp Monday, but Chicago wanted to tests to make sure there was not a fracture.

Buehrle has won at least 14 games for four straight seasons, going 16-10 with a 3.89 ERA in a league-leading 245 1-3 innings last season. Buehrle threw six perfect innings Saturday against Kansas City and is 3-0 with a 2.41 ERA this spring.