Japanese media reported the offer was worth $5.9 million.
“It is true that we have received an official offer from Chelsea for Muto,” said a spokesman for the J-league club.
“But nothing has been decided,” the spokesman told AFP, declining to comment further on details, including the amount of money offered.
However, Sports Nippon said Chelsea offered about four million pounds ($5.9 million), which would be a J-League record from an overseas club.
“I’m honoured to receive an offer from this wonderful team,” the 22-year-old Muto told the sports daily. “But I have not made any decision yet.”
Muto began his professional career at FC Tokyo last year, scoring 13 goals in 33 games to match the first-division record for a player in his rookie season.
The baby-faced striker also made his debut for Japan last year and scored his first international goal in a 2-2 draw against Venezuela in September.
Muto has scored three goals in four games this season, helping FC Tokyo move into joint second place in the J-League standings just two points behind leaders Urawa Reds. – Agence France-Presse