The Italy international has long been linked with the reigning Premier League champions, but transfer rumours have intensified during the current window.
The flames were fanned further on Sunday when it was revealed that United boss David Moyes had travelled to Italy to catch Juventus' trip to Cagliari.
Marchisio is said to have been the main focus of a scouting mission which also allowed Moyes to cast an eye over another supposed long-standing target, David Astori.
Juventus are aware that a midfielder schooled in their academy system is generating plenty of interest, but they remain confident that the 27-year-old will opt to remain at his home-town club.
General director Giuseppe Marotta told Radio Rai: "There is no problem with Marchisio. Claudio is a player who grew up in the Juventus youth teams and he loves the shirt.
"During a busy season it is inevitable that every player will have their lows, but everything is normal."
Juventus are also having to fend off incessant speculation regarding the respective futures of Andrea Pirlo and Paul Pogba - with the former in the final months of his contract and the latter attracting interest from afar - but Marotta maintains that both men are going nowhere.
He added: "Pirlo's contract? He said last week that he feels happy here. We have talked with each other and in February we will find a solution to continue together.
"Pogba? We don't want to sell him and we close the door to any possible buyers."