United face Granada in the second leg of their Europa League quarter-final on Thursday but will be without a number of players, particularly in defence. As such, teenage centre-back Fish has been called up to the seniors and been added to United's 'B list' squad.
Solskjaer says Fish is a player they're expecting big things from.
“He's a very good talent," he told United's official site. "A composed centre-back with physical stature. He's one we believe in.
"Of course, we've lost a few defenders so to have Will on the bench is a good experience for him and he's there if he's needed and he's ready."