The 35-year-old was involved in a serious road accident in December when his car hit a tree on the way home from training, breaking his thigh bone in four places, and he did not play for West Ham again.
Antonio joined the London club from Nottingham Forest in 2015 and made 323 appearances, scoring 83 goals to become West Ham’s all-time leading scorer in the Premier League.
"Michail will always be a much-loved and respected member of the West Ham United family. As has been the case since December, the Club will continue to support and assist him in his ongoing rehabilitation, offering him access to training, facilities and medical care if needed," West Ham said in a statement.
"Dialogue continues over his future involvement with the Club in an alternative capacity - including one that would enable others to benefit from his experience and leadership qualities - and he will forever hold a special place in our 130-year history."
Antonio helped West Ham win the Europa Conference League in 2023, ending their 43-year wait for major silverware.
He made his return to competitive action in June as a substitute for Jamaica in a CONCACAF Gold Cup game against Guatemala.