The Morocco international, who made a successful return from injury in January to feature 12 times last season – including starting the UEFA Conference League Final victory in Leipzig – has traded in his No. 34 shirt.
Instead, in the new campaign, Riad will wear No. 4.
Previous occupants of the No. 4 shirt include former captain Luka Milivojevic; Norwegian favourites Brede Hangeland and Jonathan Parr; and fellow centre-back Clint Hill, among others.
Earlier this summer, it was revealed that fellow defender Jaydee Canvot had traded in his number for the No. 6 last worn by England’s Marc Guéhi.
New signings Dwight McNeil and Evann Guessand will wear No. 11 and No. 29 respectively, with Óscar Mingueza taking on No. 30 and Takehiro Tomiyasu taking on No. 17.
Further new signings’ numbers will be announced soon – with a full list of 2026/27 squad numbers also set to follow.