London - Sunderland left-back Patrick van Aanholt was withdrawn from the team to face Tottenham Hotspur last Sunday due to the results of cardiology tests, manager David Moyes revealed on Tuesday.
Van Aanholt, 26, was named in Sunderland's starting XI, only to be replaced by Jason Denayer, with television cameras catching the moment Denayer told a surprised Van Aanholt he would not be playing.
Moyes refused to elaborate on the reasons for Van Aanholt's withdrawal after the game, which Sunderland lost 1-0, but has now said he was advised to take the Dutchman out of his team on medical grounds.
"He had the statutory checks with the cardiologists and the FA (Football Association) panel of cardiologists looked at it," Moyes told a press conference.
"They advised us really late on Sunday that he should not play until further tests had taken place."
Moyes said he "just can't understand" why Sunderland were advised not to field Van Aanholt at such short notice.
Van Aanholt has since undergone further tests.
He will travel with the rest of the squad for Wednesday's League Cup game at Queens Park Rangers, but Moyes said he had not yet decided whether or not the former Chelsea player will play.
"He's had some further tests and will travel to London with us, and we will make a decision on that a little bit later," Moyes said.