Crystal Palace have confirmed that Orlando Trustfull, Sammy Lee and Ryland Morgans have stepped down from their respective positions at the club on 16 September.
Trustfull was De Boer's assistant at Ajax, who took the vacant job at Selhurst Park in the summer. He replaced Sam Allardyce and the ex-England manager helped Palace avoid relegation last season.
Lee and Morgans who followed Allardyce to Palace earlier in the year have also left the club along with Trustfull. De Boer had retained the former two. Lee was the assistant manager, while Morgans was the head of performance at the club.
A statement on Palace's official website read: "Following the appointments of Roy Hodgson as manager and Ray Lewington as assistant manager, we can confirm that Orlando Trustfull, Sammy Lee and Ryland Morgans have left the club.
"We would like to thank Orlando, Sammy and Ryland for their efforts during their time in south London, and wish them all the very best for the future."