BERLIN, March 4 (Reuters) - Poland striker Robert Lewandowski has left the squad ahead of Wednesday's friendly against Scotland due to a knee injury and is on his way back to Germany for further tests, his club Borussia Dortmund said on Tuesday.
Lewandowski, who will join Bayern Munich next season, is top of the Bundesliga scorers' list with 15 goals. He has added another six in the Champions League.
"Upon his arrival he will be checked by the team doctor to determine the extent of his injury," Dortmund said in a statement.
Dortmund, second in the league behind Bayern, are also in action in the Champions League later this month when they host Zenit St Petersburg in the second leg of the round of 16 after beating them 4-2 in Russia with Lewandowski scoring twice. (Reporting by Karolos Grohmann, editing by Ed Osmond)