Reports yesterday claim United manager Jose Mourinho is considering a move for the Monaco winger.
Lemar has been linked with a move to Arsenal all summer but a deal is yet to be done for the 21-year-old midfield star.
And some United fans think Mourinho is just bluffing, in the hope that Arsenal don’t sell Alexis Sanchez to their title rivals Manchester City.
One supporter on fan site RedCafe said: “It’s a sly bluff from the club to discourage Arsenal from selling Sanchez to City.”
Thomas Lemar is a 21-year-old France international who plays for Monaco
Another fan mused: “Could this be a leak from Monaco side to exert pressure on Arsenal to up their offer?”
A third posted: “Making Arsenal think twice about strengthening City by noisily threatening to swoop for the player they’ve lined up as a replacement.”
Some other Man Utd fans were not convinced by the conspiracy theories, though.
Another fan added: “I just don’t find it plausible United starting rumours for the sake of preventing a rival selling to another rival.
“And similarly I don’t see said rival altering their transfer plans last minute because of United rumours.”
One Arsenal fan was tearing his hair out over United’s interest in Lemar.
He posted on Twitter: “If Thomas Lemar moves to Man United because Arsenal were heckling over a fee, I will be 100% done with this club & it’s false prophecies.”
Sanchez has only one year left on his Arsenal contract, and manager Arsene Wenger admitted earlier this week he isn’t certain the Chile international will remain at the Emirates.
When asked if he could make an assurance that Sanchez and Alex Oxlade-Chamberlain would stay at Arsenal, Wenger said: “One hundred per cent never exists in our job.
“But we have to make a choice between efficiency on the field and financial interest and most of the time if you can find a good compromise, it’s better.
“But in this case, I think I prioritise the fact that he will be useful on the sporting side.”