Portuguese news outlet Record claim Jose Mourinho is edging towards a £26m move for the attacker.
Guedes has come through the youth ranks at Benfica and is now an important member of Rui Vitoria's first-team at the Estadio da Luz.
He scored three goals and contributed six assists in his 18 outings in the Portuguese top-flight last season.
But speaking last year the starlet suggested that he wants to stay in Lisbon.
"I’m not thinking about leaving in January," he said.
"Benfica are the club of my heart and I’m focused on playing for them.
"All games are important, we want to win the three points but we know that the Champions League is a very demanding competition."
Jose Mourinho could be in the market for a new wide man.
Memphis Depay was offloaded to Lyon after an underwhelming 18 months at Manchester United.
