Declan Rice is expected to leave West Ham this summer after lifting the Uefa Europa Conference League trophy on Wednesday night, leading the Hammers to victory over Fiorentina.
End of the story for Rice and West Ham
When asked whether the historic victory over Fiorentina was Rice's last match in a West Ham shirt, Sullivan told talkSPORT: "I think it has to be.
"We promised him he could go. He set his heart on going.
"You can't ask for a man who has committed more to us this season.
BREAKING: Declan Rice to leave West Ham confirms Hammers chief #WHUFC https://t.co/jHjm6xMY7u
— talkSPORT (@talkSPORT) June 8, 2023
"In due course, he has to get on and we have to get a replacement - or several replacements.
"You can't keep a player who doesn't want to be there."
Arsenal to battle Bayern for Rice
Arsenal are understood to be leading the race to sign the England international and are ready to make an opening bid of around £90m to that effect.
Bayern Munich and Manchester United have also been credited with an interest but the Red Devils have other pressing areas of concern and are not minded to enter the bidding war at this moment.