Whelan has claimed Chelsea have made an offer which includes add-ons based on appearances for the former England Under-21 international, who scored six Premier League goals last season.
He told Sky Sports News: "Chelsea have got to make their mind up - yes or no - and at present they're messing about a little bit which is unusual for Chelsea because they're up front if they want someone.
"They would usually go and make a bid and get the player.
"With Victor, Chelsea have come in with offers including payments later, etc.
"It's unusual for Chelsea because they're usually a very straightforward club.
"If they come with the fee, we'll sell him. If they don't, we'll keep him.
"I'd like to keep Victor - I think he'll benefit enormously from spending another season - or two or three seasons - under Roberto Martinez."