Bayer Leverkusen general manager Wolfgang Holzhauser says it is likely Andre Schuerrle has signed a pre-contract agreement with Chelsea.
Schuerrle has been heavily linked with a move to Stamford Bridge and Holzhauser revealed the Bundesliga club are considering an offer from Chelsea for the 22-year-old.
Holzhauser said Leverkusen will assess their options before making a decision on the bid but expects an arrangement is already in place between the player and the west London club.
Chelsea reportedly had a bid turned down last year for Schuerrle, who is contracted to Leverkusen until the end of the 2015/16 season.
"Andre Schuerrle has probably signed a pre-contract deal with Chelsea," Holzhauser told Kicker magazine.
"It all depends on whether we let him go. We have received a concrete offer for a fee which we are considering. But the price alone is not decisive. We must also have alternatives, which we don't have yet."
Kevin de Bruyne has been linked with a move in the other direction as a possible makeweight in a deal for Schuerrle but Holzhauser believes Borussia Dortmund are pursuing the Belgian midfielder.
"He still has a few talks to hold with Chelsea," Holzhauser said of De Bruyne, who has been on loan at Werder Bremen this season.
"It looks like there is an offer from Dortmund to sign the player for a relatively high fee.
"According to our information, Chelsea don't want to sell him but just loan him out."