United face Madrid in Skopje in the UEFA Super Cup on Tuesday and the pre-match build-up has been played out against mounting speculation over Bale's future.
A report by Spanish publication Don Balon claimed the 28-year-old forward was ready to consider a move to Old Trafford in the event of Madrid attempting to move on a star name to facilitate the signing of Monaco sensation Kylian Mbappe.
Mourinho does not view this as a likely turn of events but told a pre-match news conference he will have a keen eye on the Madrid teamsheet in the Macedonian capital.
"Well if he's playing tomorrow, no I wouldn't think of [signing Bale] because it would show he's in the coach’s plans and the club's plans and he also has that motivation to continue at Real Madrid," he said.
"If he is not in the club's plans, that the arrival of another player would mean he was on his way out, I will try to be waiting for him on the other side and fight with other coaches that would want him on their team.
"But if he plays tomorrow, that is the best confirmation that he is still wanted by the team."