Radamel Falcao
Falcao has not been able to prove himself at Old Trafford due to injuriesReuters

Manchester United are reportedly keeping a close eye on Colombian star Ramadel Falcao's fitness before they decide to sign him on a permanent basis in a £44-million deal at the end of this season.

The striker was earlier the most-feared striker when he was in Porto and Atletico Madrid, scoring 41 in 51 appearances and 52 goals in 68 games in the Portuguese league and the La Liga respectively.

His terrific form resulted in him completing a €60-million move to Ligue 1 side AS Monaco, making him one of the world's highest-earning players with a salary of €18.2 million per annum.

However, since his move to France, the striker has suffered a dip in form due to injuries picked up on a regular basis.

Midway through the 2013/14 season, the striker was ruled out for five months with a serious knee injury that effectively ended his season as well his hopes of playing in the 2014 World Cup.

After his recovery, the 28-year-old Colombian moved to Manchester United on a season-long loan (with an option to make the move permanent for £44 million), but the striker has not been able to establish himself at Old Trafford due to injury problems this season.

Due to this reason, United want Falcao, who has only made three starts in all competitions this season, to prove his fitness before they sign him on a permanent basis, according to the Daily Mirror.

However, it is believed that the Red Devils are not keen on signing Falcao anymore as there are major concerns over the former Atletico Madrid's current form and long-term fitness issues. And United reportedly feel that he is not worth £44 million plus £240,000-a-week in wages.

Meanwhile, Colombia boss Jose Pekerman is confident that Falcao, who is currently sidelined with a calf problem, will rediscover his earlier form once he regains his full fitness and adapts to the Premier League.

"Falcao is at one of the best clubs in the world, in one of the best leagues and with one of the best managers under Louis van Gaal," Pekerman told the Daily Mirror.

"Playing in England is clearly a new experience for him, but everywhere he has been he has adapted and excelled, achieved great things.That was the case in South America, and also in Europe, in Spain and at Monaco. There is no doubting his ability."

"And I am sure that Manchester United fans will see him at his very best once he has got through this difficult moment with injuries," said Pekerman.

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