Radamel Falcao
Falcao's future at Old Trafford still up in the airGetty Images

Former Manchester United striker Diego Forlan claims Radamel Falcao was put under pressure to return from the knee-ligament injury.

The 28-year-old suffered a serious injury last January and regained full fitness before the start of the 2014 World Cup in Brazil. However, the Colombian international failed to make it to the final 23-man squad.

Falcao joined United on a season-long loan from AS Monaco on the final day of the last summer window. The former Atletico Madrid star has struggled to replicate his La Liga form at Old Trafford. Forlan has urged Falcao to regain his confidence in order to bounce back from his poor form.

"Falcao went to Monaco where he was seriously injured after tearing the anterior cruciate ligament. There was pressure on him to make it back for the World Cup last summer with Colombia. Maybe too much, for it was unrealistic," Forlan said in his column in the National.

"Falcao had played very little football when he signed for Manchester United, the world's greatest football club."

"Because Falcao had built this huge reputation and because he was earning a lot of money, great things were expected, but it was never going to be straightforward. Nobody comes back from a serious injury and is the same after a month or even three months."

"You should play in the reserves. You get your muscle back and regain your match rhythm. Psychologically, you need to build your confidence back up and you hope there are no complications. Even in a settled side it's hard," the Uruguayan added.

Forlan struggled at Old Trafford as he failed to impress during his time in England. The 35-year-old impressed during his time in Spain with Villarreal and Atletico, where he was eventually replaced by Falcao at Vicente Calderon.

The former United striker has backed Falcao to shine for the 20-times English champions in the second half of the season.

"Technique, speed, strength and style all came second to him scoring. He has that instinct. I'm a striker and you want to be playing twice a week," Forlan said.

"Being on loan will bring more pressure as he's effectively on a season-long trial and expected to score in every game, but I'm convinced Falcao will come good again, even if it is not at Manchester United. He just needs time and minutes, but trust me, he's top-quality."