The former Premier League goalkeeper says that the Spain international needs to be careful about losing a big contract offer from his club
Mark Schwarzer has warned David de Gea that Manchester United may choose to let him go if they decide his value is less than what he's asking for in the ongoing contract negotiations.
There has long been speculation that the Spaniard could leave Old Trafford, with the likes of Real Madrid and Paris Saint-Germain having been linked.
The former Atletico Madrid goalkeeper has made a number of uncharacteristic errors over the last 12 months, including in the 2-1 home defeat to Crystal Palace earlier this season that saw Patrick van Aanholt beat him at his near post.