Borussia Dortmund chief executive Hans-Joachim Watzke is expecting Mats Hummels to decide on his future in the next week.
Dortmund have stressed that they have yet to reach any agreement with Bayern Munich over a transfer amid growing suggestions the Germany defender could sign a new deal at the Westfalenstadion.
Hummels, 27, has just over a year remaining on his current contract and Dortmund issued a statement last week confirming that their captain was keen to re-join Bayern.
"The decision is up to him, the ball is in his court," Watzke told Sky. "I think he will decide soon. I believe that decision will come during the next week."
Dortmund have already said that the transfer fee, reported to be around €40 million, is "non-negotiable."
There are now serious questions as to whether Hummels does remain keen on the deal, with both Suddeutsche Zeitung and kicker reporting on Friday that, although his family are keen on a return to Munich, the player himself would prefer to continue his career at Dortmund.
Dortmund boss Thomas Tuchel was asked about the situation at his news conference on Friday morning but said: "I can't tell you anything new."
The club's slim Bundesliga title hopes were ended on Saturday when Bayern won at Ingolstadt -- though Dortmund themselves suffered a shock defeat at Eintracht Frankfurt anyway.
Dortmund finish their league campaign next week at home to Cologne before then facing Bayern in the DFB Pokal final the following week.