Dortmund: Lewandowski could stay until 2014
"It is a simple numbers game. It could make financially more sense to play a good season with Lewandowski instead of selling him and receiving a high transfer fee," Dortmund CEO Hans-Joachim Watzke told kicker magazine.
"We are under no financial pressure to act on this."
The striker, a target for several top European clubs, has notched up nine league goals this season, including a brace against Mainz 05 on Saturday, to join Eintracht Frankfurt's Alexander Meier and Bayern Munich's Mario Mandzukic at the top of the scorers' list.
Lewandowski has helped Dortmund to win back-to-back league titles and a German Cup in the past two seasons and has steered them past the Champions League group stage into the last 16 this season.
If the Poland international leaves in 2014, after his contract runs out, Dortmund will not be paid anything.
Dortmund, who almost went bust in 2005, posted 39.3 million euros in profit for 2011/12 - the highest by any club in the Bundesliga's 50 years - the club said in August.