Petkovic out of Hopman Cup with injury

Germany's Andrea Petkovic has withdrawn from the Hopman Cup after suffering a knee injury in the opening set of her match against Australia's Ashleigh Barty on Saturday. Tournament officials said Sunday the extent of the injury is still being assessed but the German star said on Twitter ''so it's a rupture of the meniscus, back to Germany as soon as possible for an arthroscopy. Relieved it wasn't the ACL (anterior cruciate ligament) again.'' The nature of the injury means Petkovic will likely miss the Australian Open beginning Jan. 14. The tournament is now seeking a replacement to partner Tommy Haas for Germany's two remaining matches against Italy and Serbia.