The former England captain has been restricted to playing just 45 minutes of the Blues' last three games due to illness.
But his boss Allardyce, who called upon him as a half-time substitute in Saturday's 2-1 defeat at Bournemouth, said of United's Monday visit: “Wayne will be fit to start.
“It is only a virus, not an injury, so going 45 minutes will be good for him."
Allardyce reckons the Red Devils will bring the best out of his team, but is not afraid to park the bus.
The former England manager said: “Sometimes when you play a team as big as that it gets the best out of you. The players and fans will be up for the big ones.
“It's about recovering the players and what team I pick and what tactic we use to try to master a Manchester United side.
“I saw their creativity against Burnley. They had 25, 30 attempts at goal, so we are going to have to be really on song. The players are not going to have a lot of the ball and we are going to have to be very disciplined in possession as well.
“We only end up sitting back because the opposition push you back, so I don't know why people look at you and say why do you do that? You do it because the opposition do it to you.
“If you are going to get any attacks going, you have to use the limited possession that you have extremely well."