From the looks of things, Didier Drogba was unconscious before he hit the ground after getting a head shot from Norwich City's goalkeeper. He was down with an apparent head and/or neck injury for a while, to the point that there were 11 extra minutes in the second half of Chelsea's 3-1 victory.

Drogba went up to challenge [Norwich City goalkeeper John] Ruddy for a high ball, but the goalkeeper's fists accidentally connected with Drogba's face and he appeared to be knocked out cold in midair before falling to the ground and landing nastily. A lengthy stoppage was required before Drogba was taken off in a neck brace.

No word on Drogba's condition yet.

Didier Drogba receives treatment for a head injury [ESPN.uk]

Drogba Knocked Out Vs Norwich [YouTube]