The Republic of Ireland international had to leave the field of play early in the first half after a reckless challenge by Villa defender Alan Hutton in The Baggies’ 2-1 victory.
The Hawthorns club have revealed that the former Reading man has suffered severe bruising and a bone chip in his right knee, and will now be unavailable for most of the rest of the year.
The news will be a blow for Giovanni Trapattoni and the Ireland team, who are set to face Estonia on November 11th and 15th in the Euro 2012 playoffs.
West Brom boss Roy Hodgson has attacked Hutton after the challenge, as he will now have to make do without his main attacking player.
“I don’t think it will be good news when the scan comes through because it was such a vicious challenge,” he told Sky Sports.
“I suppose he has got to consider himself lucky he hasn’t got two broken bones in his leg but I would think it is a serious knee injury. I was disappointed with that challenge by Hutton and not only saddened by it, but angered by it.
“I don’t think there is any room in football for those type of challenges on the field and overall the game wasn’t like that,” he concluded.
West Brom moved up to 12th place after the win, and take on Liverpool at home this Saturday.
By Gareth McKnight