Austrian football player Guido Burgstaller has been left with serious head injuries, including a skull fracture, after he was attacked in the Vienna city centre, his club Rapid Vienna said on Monday. Rapid Vienna said the 35-year-old striker was struck by an unidentified man and fell, injuring his head, in an incident which took place in front of witnesses during the weekend. The club said Burgstaller, who has played 26…