The Dutch international failed to make the grade in the Premier League during a two-year spell at Old Trafford.
He departed for Lyon in 2017 for £16million and has rekindled something of the form that first led United recruiting the PSV Eindhoven academy graduate.
He has nine goals and 13 assists to his name this season and according to French outlet Mercato 365, Jurgen Klopp sent staff across the channel to check on the Dutchman during Lyon's 3-0 win over rivals Marseille on Sunday.
Klopp is believed to be in the market for attacking reinforcements to provide competition for Mo Salah, Sadio Mane and Roberto Firmino.