The Radio 1 Breakfast Show host told 5 News that the singer isn't young enough to connect with younger listeners to his show.
The 28-year-old presenter admitted that he'd never listened to a Robbie Williams track before his latest hit - which is deemed not right for the Radio 1 playlist.
Grimshaw said: "I don't know if he's now for a Radio 1 audience. I've never listened to a Robbie Williams song but I really like him.
"To 13 and 14-year-olds he's not relevant... they've got One Direction. I liked Take That when I was little, but I'm not little anymore."
However, Grimshaw did play Williams's new single 'Candy' on his show this morning (November 5) and said: "I quite like the new song."
The Take That star reached the top of the singles chart with 'Candy' on Sunday (November 4), with it becoming the fastest-selling single by a male artist this year.
Watch Nick Grimshaw speak to Digital Spy below: