It was another season of awards off the pitch for de Gea, consecutively winning the Sir Matt Busby Player of the Year award and being named in the Premier League's Team of the Year for the second time in three seasons.
Since arriving at United and developing into one of the best goalkeepers in the world, de Gea has received interest from Real Madrid with Iker Casillas openly speaking about having competition between the sticks, as per the Daily Star.
David de Gea's contract expires next season and Hoek, who worked with Louis van Gaal at Ajax, Barcelona, Bayern Munich and Holland, believes the 24-year-old has the attributes to make it as a United legend.
"He is now at one of the biggest club in the world," Hoek told Man Utd Poland.
"The moment you are playing at a high level there, you're great and if you continue to do that, then automatically you become one of the better ones in the world.
"He showed at a very young age - he became 24 this season - that he is able to do the job in all elements of the game, in construction, but also in defence.
"So nothing stands in his way to become one of the best like Schmeichel, like Van der Sar at United."
If de Gea does leave Manchester United this summer, Victor Valdes will be ready to take up the main spot between the posts at Old Trafford.
The former Barcelona goalkeeper, who had a working relationship with Hoek prior to the move, made his first start for the first-team on the final day of the season versus Hull City.