Sunderland left-back Patrick van Aanholt was pulled out of Sunday's 1-0 defeat at Tottenham because of "medical advice from cardiologists", according to manager David Moyes.
Van Aanholt, 26, was replaced by Jason Denayer 15 minutes before kick-off.
"He had the statutory checks with the cardiologists," said Moyes.
"The Football Association panel looked at it and advised us really late on Sunday that he should not play until further tests had taken place."
Moyes said the Dutch player has since had those tests and will travel with the squad for Wednesday's EFL Cup match against Queens Park Rangers (19:45 BST).