Arsenal are on the brink of signing Rice from West Ham for a club-record fee worth £105million.
Manchester City, United and Chelsea have all been interested in the England international but the Gunners have won the race.
But it means that Mikel Arteta will likely have to sell players to afford the fee and also to make room for Rice.
And former United star Paul Ince reckons his old club should make a shock swoop for Thomas Partey, who looks destined to depart the Emirates.
"I look at Casemiro, Fernandes, Christian Eriksen, great players that they are, they're still crying out for that one who's got the legs," Ince told Betway.
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"Basically, a younger version of Casemiro, which isn't going to be cheap. Obviously, there's a lot of talk about [Moises] Caicedo.
"I like Franck Kessie at Barcelona. He's not getting enough game time. There's also talk about Thomas Partey leaving Arsenal.
"You think about the first six months of the season, Partey was absolutely fantastic.
"Jorginho came in and, for some reason, he stopped getting games.
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"That's when Arsenal started losing and drawing games. I'd be looking at someone like him or Kessie."
Partey has not been linked with a move to United but a move away is on the cards.
Saudi Arabian clubs are interested in the Ghana international amid a huge summer splurge from the Gulf state.
Big-name stars such as Karim Benzema, Ruben Neves and Kalidou Koulibaly have already made the switch, as well as Steven Gerrard as manager of Ettifaq.
But Juventus are also in for Partey, who has not yet decided if he is ready to leave European football yet.
United, meanwhile, have made signing a striker their priority and talkSPORT understands that talks are ramping up for Atalanta star Rasmus Hojlund.
The 20-year-old has become a top target ahead of Harry Kane and Victor Osimhen due to his availability.
Nevertheless, the Red Devils are keen on offloading players with Dean Henderson, Fred and Anthony Elanga all expected to depart before the transfer window ends.