Chicago White Sox manager Tony La Russa is out indefinitely with an unspecified medical issue, a source confirmed to ESPN’s Jesse Rogers.

Bench coach Miguel Cairo will manage the White Sox on an interim basis while La Russa undergoes further testing, the source told Rogers.

USA Today Sports first reported Wednesday that La Russa was out indefinitely.

Cairo said after Tuesday’s loss to the Kansas City Royals that the White Sox hoped to learn more about La Russa’s status Wednesday.

“We are going to keep him in our thoughts and hopefully everything is fine,” Cairo said.

La Russa’s absence initially was announced about one hour before the first pitch of Tuesday’s game. The Hall of Famer showed no signs of health issues during his pregame session with reporters and while talking to Chicago general manager Rick Hahn.