West Ham chairman David Sullivan has confirmed captain Declan Rice will be allowed to leave this summer and he expects to start receiving bids immediately.
The England midfielder said he did not know if he had played his last game for the club after leading them to Europa Conference League glory.
A 2-1 victory over Fiorentina in Wednesday night's final saw him become only the third Hammers skipper to lift a major trophy, following Bobby Moore and Billy Bonds.
However, Sullivan admits a gentleman's agreement means they will allow a player who still has two years remaining on his contract - one year plus an option - to leave.
Asked whether lifting the trophy in Prague was Rice's last action as a West Ham player, Sullivan told talkSPORT: "I think it has to be. We promised him he could go.
"He set his heart on going and in due course he has to get on and we have to get a replacement.
"It is not something we wanted to happen. We offered him £200,000-a-week 18 months ago and he turned it down. You can't keep a player who doesn't want to be there.
"I think the offers will start to come today. Three or four clubs have shown interest but, out of respect to West Ham, while we're still playing, you don't make offers for players."
Rice said after the game that it was "not goodbye yet".
He added on BT Sport: "Look at the moment there's a lot of speculation about my future.
"There is interest from other clubs, that's out there, but ultimately I've still got two years left at West Ham.
"There hasn't been nothing yet (offers). Let's wait and see, who knows.
"I love every minute of it here, you can see the smile on my face.
"It's not about that tonight, it's about celebrating and that's what I'm going to do now."
Match-winner Jarrod Bowen was close to tears as he celebrated scoring the goal which won West Ham the Europa Conference League.
Bowen raced on to Lucas Paqueta's brilliant pass in the 90th minute and slotted past Pietro Terracciano to earn the Hammers a 2-1 victory over Fiorentina in Prague.
It secured the club's first piece of silverware since the 1980 FA Cup and their first European trophy since 1965.
Bowen told BT Sport: "You always say you want to score in the last minute and to do it here in front of these fans, I thought I was going to cry.
"I'm so happy. We haven't had the best season, myself included, but to do it tonight, I'm over the moon.
"I think in my position you make that run 10 times you might get that ball once. As soon as you get it you've got to put it away."
Bowen had earlier won the penalty from which Said Benrahma opened the scoring but Giacomo Bonaventura equalised just four minutes later for the Serie A side.
But with the game appearing set to head to extra-time, Bowen struck his 13th goal of the campaign and earned West Ham a place in next season's Europa League.
The England international added: "Never (have I felt like this in my life). This is the biggest game of my career. The emotion, there was time for one more chance. I'm just so happy. I'm over the moon.
"I'm thinking of the party tonight. Listen to it. Listen."