The 20-year-old midfielder is considered an exciting prospect at Old Trafford and spent last season on loan at Birmingham City.
He has three years left on his contract but his future at Old Trafford is expected to be under the scanner this summer.
Now it has been claimed that the midfielder is now attracting interest from a few big European clubs ahead of next season.
Dortmund are keen on him, but it is suggested they are just one of a number of sides who are monitoring Hannibal closely this summer.
It has been suggested that the Bundesliga giants are ready to offer somewhere around €15m plus add-ons for Hannibal.
The midfielder is expected to be given a chance to impress Erik ten Hag during pre-season this summer.
A decision is only likely to be taken only later in the window and Manchester United are likely to favour a loan over a permanent deal.
However, Manchester United also need player sales this summer and Ten Hag could agree to move on youngsters who he believes do not meet his high standards.
