The Hillsborough outfit have taken the opportunity to clear the decks in the wake of an unsuccessful and fraught 2020-21, with a host of players whose deals expire next month having been shown the door.
Along those included in the list alongside Lees and Westwood is Adam Reach, bought for £5m from Middlesbrough in August 2016.
Kadeem Harris, Joost van Aken, Elias Kachunga, Matt Penney, Moses Odubajo and Joey Pelupessy will also leave the club, who have activated one-year extensions to retain Sam Hutchinson, Ciaran Brennan, Alex Hunt and Sam Hutchinson.
Highly-rated defender Osaze Urhoghide has been offered a new contract.
Rhodes is reportedly set to return to former club Huddersfield Town, while the Terriers are among several clubs who have been linked with Lees, alongside the likes of Nottingham Forest.