Manchester United and Benfica have agreed a deal to loan Alvaro Fernandez to the Portuguese club.
United have allowed the defender to leave for a modest loan fee and an option for Benfica to buy.
The Portuguese club can secure Fernandez for a modest 6 million at anytime before the loan expires.
In addition, there is a clause that obligates them to make that purchase, if Fernandez plays 50 percent of their remaining games this season.
United will also have a buyback clause that allows them to bring back Fernandez for a set fee if he impresses.
There are also clauses including a sell-on percentage agreement and a matching rights agreement.