Manchester United boss Louis van Gaal says striker Falcao has to prove himself to secure a regular place in his team.
The 28-year-old joined the Red Devils during last summer's transfer window but scored only three goals in the first part of the season.
And he was not in the squad for the 1-0 home defeat against Southampton last week.
"If a player costs £95m or £5,000, it doesn't make any difference. You have to prove yourself.
"He [Falcao] has to prove himself, that we have agreed.
"We have made this deal and everything is clear and it is not the end of the year [the duration of his loan spell] so he has the chance for that.
"For the manager it is the quality of the training sessions, the quality in his performances and matches and he has to compare [favourably].
"A player of £95m has to prove himself also. Maybe he has less motivation so I have to be like that."
Meanwhile, the Dutchman says it will be very difficult for Manchester United to sign quality players during the January transfer window.
"I don't think that we shall be very active as not many players of a certain level are available," van Gaal explained.
"When we buy a player he has to be better than the players that are playing now and that is a difficult job."
