The 21-year-old's agent Frank Liberam confirmed that Blackburn's chief scout, Martin Glover was on hand to watch Petersen net his eighth goal in nine games against Bochum on Sunday evening.
And Cottbus manager Claus-Dieter Wollitz admits a move to the Premier League could be on the cards.
Wollitz told Bild newspaper: "Nils Petersen is on his way to becoming a massive player. There was a scout from Blackburn watching him against Bochum and he also watched him in action against Freiburg (in the German Cup) last Tuesday."
Meanwhile, Liberam said: "Blackburn have been looking at Nils for a few matches now. They seem to be very interested and have been in touch with us.
"Mr Glover has been impressed by Nils' performance against Bochum."
With Rovers manager Sam Allardyce looking to strengthen his attacking options, the club could table a bid in the region of £2million for the 6ft 2in German under-21 international.