This move replaces Djordje Petrovic, who spent last season on-loan at Strasbourg and has since been transferred to Bournemouth.
Both Chelsea and Strasbourg are owned and managed by the same company, BlueCo.
Mike Penders joined Chelsea from Genk in August 2024 and made 26 appearances for the team last season. He also received a call-up to the Belgium Under-21 squad.