How many minutes did the current goalkeeper for Borussia Dortmund remain unbeaten at his previous club?
2012–13 Grasshopper Club Zürich season:  After this defeat the Grasshoppers remained unbeaten for twelve consecutive matches and goalkeeper Roman Bürki was able to set a new all-time record in keeping a clean sheet in Swiss football. 2012–13 Grasshopper Club Zürich season:  He remained unbeaten for 659 minutes. Roman Bürki: Roman Bürki (born 14 November 1990) is a Swiss professional footballer who currently plays as a goalkeeper for Borussia Dortmund.
i don't know