Roberto Martinez believes Ferrie Bodde would turn down a move to the Premier League if a club came in for him.
The Swansea boss was reacting to claims by Bodde's agent that there is a gentleman's agreement that the club would let him leave for the top flight.
He said: "When the situation arises, we will have to consider it... but I wouldn't be surprised if someone comes in for Ferrie and he turns them down."
"He is happy here, is enjoying his football and is he is developing."
Sjaron Vink from Fair Deal Sports Management confirmed to BBC Sport Wales that Bodde was happy.
But he added: "We made a gentlemen's agreement that if a big Premier League club came in then they would let him go.
"There is a lot of interest at the moment for Ferrie because he is doing very well.
"It is the dream of every player to play in the Premier League."
606: DEBATE
But Martinez said: "The agreement is that Ferrie Bodde has got a long term contract with Swansea City.
"Then there is a gentleman's agreement if a big Premier League club comes in, there are a wide, wide range of options that have to be discussed.
"It's not as simple. But we will never keep a player that is not happy at Swansea City and we haven't done that for a long, long time."
He added: "We need to be a bit realistic with where we are.
"We need to fulfil every players' potential and in my eyes...but we need to achieve that with Swansea City."
Dutch midfielder Bodde, 26, has been a star performer for the Swans this year and is joint top scorer with six goals.
Two of his goals have come from 30-plus yards and his consistent pin-point passing has split defences open.
And that has sparked interest from Premier League sides reported to be Middlesbrough, Bolton and West Brom.
But Swansea, who paid £85,000 for Bodde in 2007, could demand as much as £4m with half the fee going to his former club ADO Den Haag as part of a sell-on clause.
The classy Dutchman was at the centre of a long-running £2m transfer saga in the close season.
Championship rivals Derby made three bids for the player who handed in a transfer request.
But he later rescinded it and signed the new deal, ending speculation over his immediate future.
It was then when Vink says the gentlemen's agreement was made, in the presence of Swans chairman Huw Jenkins.
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