Manchester United could reportedly turn down the chance to sign Radamel Falcao on a permanent deal next summer due to the striker's fitness issues.

The 28-year-old joined the Red Devils on loan from Monaco earlier this year, and it was rumoured that United would take up the option to buy the Colombian for a fee of £44m.

However, The Sun claims that manager Louis van Gaal is stalling on completing a move as a result of the player's current form, as well as his lack of long-term fitness.

Falcao, who has scored one goal for United since arriving at Old Trafford, returned from a cruciate knee ligament injury at the start of the season.