The teenager is believed to have been watched by several scouts in last night's Capital One Cup victory at Northampton.
Robinson said that Alli wasn't for sale but conceded that one day he will have to go.
"Personally I don't think he's for sale. It's going to take millions," Robinson told BBC Three Counties Radio.
"I don't want to sell him, the chairman doesn't want to sell him. There will be a day that we have to."
A product of the Dons' academy, Alli has started both of the club's games at the start of the season.