Luke Shaw is prepared to walk away from Manchester United on a free transfer next summer if his first-team prospects at Old Trafford do not improve, sources have told ESPN FC.
United have triggered a clause in the defender's contract that will keep him at the club through 2018-19.
The 23-year-old is in the squad for the preseason tour of the United States and, according to sources, is hopeful of becoming Jose Mourinho's first-choice left-back next season.
United would like Shaw to sign a new deal to protect an asset that cost nearly £30 million in 2014, but sources have told ESPN FC that he is ready to keep his options open, including walking away for free next summer, if he cannot win Mourinho over.
Shaw started eight Premier League games last season, ultimately costing him a place with England for the World Cup, and he has started just 17 of 76 league games since Mourinho became manager in 2016.
United signed full-back Diogo Dalot, 19, from Porto this summer, but with Ashley Young set to miss the start of the season because of the World Cup, Shaw could benefit once the new season begins against Leicester City on Aug. 10.