Hays has been pulled off his rehab assignment at Triple-A Charlotte due to a recurrence of left calf soreness, Scott Merkin of MLB.com reports.
Hays had played seven rehab contests with Charlotte, but the left calf strain that sent him to the 10-day injured list in early May is still giving him trouble. He'll meet with the White Sox's training staff and develop a plan of attack for his rehab moving forward. Hays has been limited to only 12 games for Chicago this season because of hamstring and calf issues.