Recent reports have suggested that Manchester-born Rashford wants to stay and fight for his place at the club he supports.
And Adam believes the young forward has made the correct decision if the reports are true.
“If I'm him I'm kicking the door down as I want to play – I want to play for Man United," Adam told talkSPORT.
“For me, it's the biggest club in the world, and I think he's got the potential to be one of the best.
“Everything he's got – he's got pace, power, he'll learn as he's still young."