The Belgium international, 29, has forged a reputation as one of Serie A’s top midfield talents during his time at Roma.
And he has been linked with a move to the Premier League for some time with Chelsea and United both said to be keen on him.
The Sun now claim United are actively targeting Nainggolan and had him scouted when Roma faced Atletico Madrid in the Champions League two weeks ago.
He’s apparently being lined up to replace Old Trafford skipper Carrick, 36, who’s expected call it quits next summer.
A source told The Sun: "Jose sent scouts to the game to look at a number of players, but most importantly Nainggolan.
"He is a big fan of his. [Antoine] Griezmann was also looked at, but we know everything we need to about him already.
"They are going to go back in for him next summer, that’s for sure. The main thing is to replace Michael Carrick, though.
"Jose had wanted to sign Nainggolan as far back as his days at Chelsea, he is that big a fan."
Nainggolan, under contract at Roma until 2021, was not the only midfielder United had eyes on that night though.
The Red Devils are thought to be interested in Griezmann’s £85m-rated Atletico team-mate Saul Niguez too.
