The 29-year-old -- who missed last year's World Cup after failing to recover from a serious knee injury -- is according to Monaco vice-president Vadim Vasilyev wanted by several great clubs.
Falcao, who made his name at Portuguese giants Porto before earning a multi-million euros transfer to Monaco where he spent the 2013/14 season, would cost United £43.2million ($66.5million, 58.5million euros) were they to exercise their option.
However, with just four goals in 19 appearances -- he was substituted in United's last match the FA Cup fifth round clash with Preston -- it seems increasingly unlikely.
"I'm not worried for Falcao, he is a world-class striker," Vasilyev told the BBC's Football Focus programme.
"If Manchester United decide not to take up the option at the end of the season, we have interest from other great clubs
So I am really not worried for him at all."
United have already paid a £6m loan fee and the striker's £265,000-a-week wages.
United manager Louis van Gaal has been pilloried in the Colombian press and dubbed 'Van Maal' (Mr Evil) by former Colombian international striker Faustiono Asprilla.
However, the Dutch coach suggested last month that Falcao -- who scored nine goals in his first season with Monaco -- was a long way from proving he deserved a permanent move.
"If a player costs £95m or £5,000, it doesn't make any difference
You have to prove yourself.
"We have made this deal and everything is clear."
Source : AFP
Source: AFP