Marquinhos has already admitted that he is pleased to learn of United’s interest, while the 20-year-old’s agent has hinted a summer deal could be possible if the Brazilian continues to be be utilised as a rotation option by Blanc.
Marquinhos has featured 25 times in all competitions this term, but rarely in his preferred position in central defence.
"We did everything to keep Marquinhos and extend his contract," said Blanc
"We have been showing him that he is very important and we are not ready to let him go. He is strong everywhere he plays and he is only 20.
"He is the third most-used player in the squad and people still say we don't use him enough. Having players like him is very significant for a coach.
"Can he become a monster like Thiago Silva? He has the potential to become a very good defender. He already is, but he still has room for improvement."