Barcelona decided not to activate their roughly £26m/€30m option to buy Rashford following his season-long loan in which he grabbed 14 goals and 11 assists for the Spanish side.
Rashford travelled with the United squad for their pre-season clash against Leeds United in Dublin at Croke Park, yet was absent from the match day squad as fans debate whether he will be reintegrated back into the side.
The Red Devils revealed that the winger has been handed the No.14 earlier this month, suggesting that he will be handed a chance to prove himself under manager Michael Carrick.
Now, speaking to Sport Witness, Gullit has revealed that Rashford could be a revelation for United who may use him to add a new dimension in attack.
"Marcus Rashford could end up being the best signing. He learned a lot at Barcelona and played much better, with far more freedom, than he ever did at Manchester United.
"Was that his fault, or was it down to the environment at the club? It’s very easy to point fingers at the player. But if he performs well elsewhere, it suggests something was wrong in his previous environment.
"So that could prove to be a fantastic move, for Manchester United if he stays, and performs like he did at Barcelona."
The 28-year-old, who last played for United in December 2024, is set to be handed a chance at his boyhood club as fans wait to see how much of an impact he can make