The Bavarian legend fueled speculation that the Polish striker could be destined for a switch to the Allianz Arena in the summer during a live television transmission on Saturday
Reports in the German media over the past week claimed the 24-year-old, whose contract expires next year, was set to become Pep Guardiola's first recruit upon taking charge at the Allianz Arena in June.
Goal.com exclusively revealed in December that Juventus were set to step up their chase for the striker in light of an expected bid from Manchester United.
And despite BVB's continual denials that they have agreed a deal to sell Lewandowski to their arch-rivals in the summer, the legendary Bayern midfielder appeared to add fuel to the speculation.
"I was on the road this week. I heard that Lewandowski has an agreement with Bayern. Only the date of the move remains undecided," Matthaus told Sky Bundesliga.
"Lewandowski's contract runs out in 2014 and Dortmund will only get a fee in 2013 - surely a high fee. I heard it was something between €25m-€30m [£21-25m], otherwise he will go to Bayern for free next year."
Matthaus then explained how the Poland international would serve as a better option in Guardiola's attack than central striker Mario Gomez.
"I think he is a player that fits more into the system of Guardiola than Gomez," he added.
"He showed Guardiola last week in Leverkusen how a forward is not only an attacker but also drops deeper."