Given played for Villa alongside Grealish and is well aware of the 24-year-old's talent, so he has no doubts that the versatile player could fit in at United.
He told told Stadium Astro: "That's the question.
"We talk about Fernandes and the impact he's had, you couldn't pick 11 United players and not have him in the team, that's how good he's been.
"Where would Jack play? Maybe off the left or off the right.
"But I think Jack's strongest position is as a No 10.
"Even Jurgen Klopp has said that about Jack's qualities, that's where he seems his best position.
"But Fernandes is in that position as well and Pogba can also play that position. They've got a number of players who can play there.
"I think he would fit into the team. The position? I can't tell you that because he's got so many options now, Solskjaer, going forward."
He added: "There's so much press and media about Jack joining, there's no smoke without fire.
"There must be something in the pipeline that he could be joining United. I've no clue where the fee's going to be but I do think he's good enough to play for a club like United. He wouldn't look out of place in that team."