Manchester United cannot bring back Alexis Sanchez to ease their injury crisis because there is no recall clause in the loan agreement with Inter Milan, sources have told ESPN.
Ole Gunnar Solskjaer has said he could look for a short-term solution after losing Marcus Rashford to injury.
The 22-year-old, who has scored 19 goals this season, could spend the next three months on the sidelines after suffering a stress fracture in his back but Sanchez will not return to Old Trafford to fill the void.
The Chile international is due to spend the season at Inter after moving to the San Siro in the summer.
With no recall clause in the deal, Sanchez, who has scored once in six games this term having only just returned from a knee injury, will remain in Italy until the end of the season.
Sources have told ESPN that the club remain in talks with Sporting Lisbon for midfielder Bruno Fernandes but Solskjaer's need for a forward has intensified after Rashford's injury.
The England international picked up the problem in a collision with Wolves defender Matt Doherty and missed the 2-0 defeat to Liverpool at Anfield on Sunday.
Talks with Sporting are set to resume this week as United look to find a compromise over the fee.
Sources have told ESPN the Portuguese side want a fee of €65 million up front with another €15m in add-ons while United are reluctant to pay more than €50m plus €10m in bonuses.