The experienced Nigerian international joined Albion in the summer of 2018 on a free transfer after leaving German side FSV Mainz, before heading off to represent his country at the 2018 FIFA World Cup finals in Russia later that month.
The 31-year-old then made eight appearances for the Seagulls last term, most notably scoring with his first touch after coming on as a first half substitute in the memorable 3-1 win over Crystal Palace at the Amex Stadium in December 2018.
Albion head coach Graham Potter said, “I’d like to thank Leon for his professionalism and dedication during my time here at the club.
“It’s no secret he hasn’t played as much as he would have liked, but the attitude and application he showed every day has been first class, and I know that everyone here at the football club will wish him all the best for the rest of the season.”
Both of the defender’s appearances this season came in cup competitions – the Carabao Cup victory over Bristol Rovers in August and the game with Sheffield Wednesday in the Emirates FA Cup earlier this month.