West Ham United fullback Joey O'Brien is facing three months out with a dislocated shoulder.
O'Brien landed awkwardly following an off-the-ball push from Chelsea defender Gary Cahill as the players positioned themselves at a corner, leaving the Hammers to defend stoppage time with 10 men.
"The only disappointment for us today was the two injuries," said West Ham boss Sam Allardyce, following the 0-0 draw at Stamford Bridge.
"Joey, unfortunately, has dislocated a shoulder, which is bad news for us.
"That's our third dislocated shoulder this season. I don't think I've had three dislocated shoulders in my entire career, let alone three in one season."
Asked the likely length of absence, Allardyce said: "Ten to 12 weeks."
