Borussia Dortmund's Robert Lewandowski suffers knee injury

Borussia Dortmund striker Robert Lewandowski has returned from international duty early after suffering a knee injury while playing for Poland.

Lewandowski picked up the problem during last Friday's 1-1 draw with Montenegro, ruling him out of their latest World Cup qualifier against San Marino this evening.

Dortmund doctors will now assess Lewandowski but the knee injury is not believed to be serious, according to the Bundesliga's official website.

The 25-year-old will undergo a full examination from Dortmund doctor Markus Braun and is rated as doubtful for his side's clash with Hamburger SV this weekend.

Jurgen Klopp's team have made a strong start to their league campaign, with Lewandowski scoring twice in a run of four successive wins for BVB.