The former Tottenham Hotspur striker's future at the Bernabeu has come into question in recent months as Los Blancos pursue a deal for AS Monaco starlet Kylian Mbappe, a deal that would set the club back well in excess of £100m.
United, who meet Madrid in the UEFA Super Cup tomorrow night, have long been touted as suitors for Bale, and Mourinho has admitted that he would "fight" other managers to land the Welsh international if he becomes available.
"Well if he's playing tomorrow, no I wouldn't think that, it would be because he's in the coach's plans and the club's plans, because he also has that motivation to continue at Real Madrid," Mourinho replied when asked about signing Bale at his pre-match press conference today. "So I haven't even thought about the possibility.
"If he is not in the club's plans, that with 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."
Bale joined Madrid from Spurs in September 2013 for a then-world record fee of £85.3m.