"Liam's injury is worse than we feared," Robins boss Gary Johnson told the Bristol Evening Post.
"He went for the scan on Monday and it showed up ligament damage. He will be out for a minimum of three weeks and maybe longer."
Alexis Sanchez and Gareth Bale headline a host of big names who will be absent from next summer’s World Cup
The Republic of Ireland edged their way into the World Cup play-off lottery after a priceless 1-0 victory in Cardiff
Few have left a greater mark on football than mesmerising midfielder and all-round gentleman Sir Bobby Charlton, who turns 80 on Wednesday.
Another World Cup qualifying bid ended in misery for Scotland after a 2-2 draw in Slovenia saw them miss out
Wales and the Republic of Ireland meet in Cardiff on Monday evening with the prospect of a trip to the
Wales and the Republic of Ireland meet on Monday night in their final game of the first round of 2018 World Cup qualifying.