Jose Mourinho: Manchester United boss to wait on Marouane Fellaini's fitness
Manchester United manager Jose Mourinho says Marouane Fellaini "felt his hamstring" in their goalless draw with Southampton on Wednesday.
The midfielder was substituted on 75 minutes as he appeared to be struggling and walked straight down the tunnel.
"Let's wait for tomorrow but he needed to play," Mourinho told MUTV.
United host Crystal Palace on the final day of the Premier League season on Sunday before facing Ajax in the Europa League final in Stockholm on 24 May.
Mourinho, who briefly talked to Fellaini before he went down the tunnel, added: "Fellaini has a bad feeling, he doesn't think it is a tear.
"A feeling in a hamstring is always something to be worried about."
The Belgian, 29, was playing his first Premier League game since serving a three-match suspension after being sent off for headbutting Manchester City striker Sergio Aguero.
Fellaini could be the latest player to join United's long list of absentees for next week's final, which includes Zlatan Ibrahimovic, Marcos Rojo, Luke Shaw and Ashley Young.