BREAKING: Ron Vlaar. Again.

Aston Villa defender and captain Ron Vlaar has come off in the 15th minute after apparently injuring his knee tackling Crystal Palace's Wilfried Zaha. Ciaran Clark, who started the match on the bench, has replaced him for the time being, but the bigger concern is Vlaar's problematic leg. After an injury in Netherlands November 12 friendly against Mexico, Aston Villa were unable to use Vlaar again until December 13, and this was only his fourth start since the return. This comes after missing the entire month of September with another leg injury.

While Ciaran Clark and Jores Okore have been a fantastic centre back pairing in the past month and a half, the injury deals two blows to Villa. The first is an issue of depth. With Nathan Baker and Philippe Senderos out injured, Villa are now out of centre-backs we'd consider starting without cringing. If Clark or Okore take a knock it's not clear who fills in.

The second blow is a transfer-based one. Vlaar has been a target for Manchester United seemingly all season, and given the oodles of money Louis van Gaal's club have and the inflation inherent in the January window, it stood to reason that Villa could get a few million for Vlaar. If he's injured, that seems less and less likely.

Let's hope this wasn't anything too serious.