Nani\'s long contract and high wages are proving to be stumbling block for Manchester United, as they try to offload him. Getty

Manchester United are reportedly facing a £17m bill for the remainder of winger Nani's contract as he prepares to return to Old Trafford following a season-long loan spell at Sporting Lisbon.

According to the Telegraph, the Red Devils have been playing the winger's entire £110,000-a-week wages during his stay in Portugal, which was due to a deal struck with the Portuguese club that facilitated the transfer of Marcos Rojo to United last summer.

Louis van Gaal has reportedly made it clear to Nani that he does not have a future at Old Trafford, as they are already well stocked in the wide areas with Ashley Young, Adnan Januzaj, British-record signing Angel di Maria and the latest addition Memphis Depay, who is set to move in the summer subject to a medical.

But the worry for United is that, despite the Portugal international's impressive performance for his former club on loan, they are unlikely to make his move permanent as they will not be able to afford the winger's £110,000-a-week wages.

This will be a sticking point for United in the summer as Nani still has three years remaining in his current deal that was signed in 2013.

It will be hard for him to move on as he will prove to be too expensive for most of the interested parties, leaving the Red Devils stuck with an unwanted player on a substantial pay package.

The 20-time English champions are keen to sell Nani this summer as they are not keen on yet another loan, but with not too many clubs showing interest in signing the player, the report claims that the manager could include him in his plans for next season.

The 28-year-old winger, who has had a successful loan spell with Sporting, had revealed earlier in the season that he would return to Old Trafford following the end of the current campaign, despite the fans wanting him to remain in Lisbon.