It's been suggested Manna was in England to meet with Chelsea and Manchester United about the future of Victor Osimhen, says Il Mattino.
The Nigeria international is currently on-loan at Galatasaray and Napoli will sell at the end of the season.
Osimhen's contract with Napoli carries a €75m buyout clause, which can be triggered this summer.
Juventus are also interested, though Napoli would prefer to see Osimhen not return to Serie A.
Chelsea failed in an attempt for Osimhen in January and will try again as they seek a new centre-forward signing. United are also interested, though must sell before buying this summer.