The 2005 Lions skipper underwent a scan on the injury, sustained in a double spear tackle from All Blacks' duo Keven Mealamu and Tana Umaga, yesterday in Christchurch, and it revealed significant soft tissue damage around O'Driscoll's right shoulder joint.
The Lions medical staff are not certain if the Leinster centre will need surgery on his shoulder, but the 26-year-old looks like being out of rugby until after Christmas.
The decision of match commissioner Willem Venter of South Africa not to cite either Mealamu or New Zealand skipper Umaga for their dumping of O'Driscoll in a seriously dangerous double spear tackle has left a sour taste in the mouths of the touring party.
"Obviously, I am absolutely gutted that my tour is over. There is a huge element of frustration and anger at the way it happened," said O'Driscoll, who is to remain Down Under until the Lions tour finishes next month.
"I have no doubt whatsoever there was some sort of spear tackle that ended it. When you have worked so hard for something like that, to have a minute and 17 seconds, it doesn't really feel justified.
"I certainly feel there was plenty in it. I have been on the receiving end before, but I felt this was completely unnecessary and certainly beyond the rules and regulations of the game.
"I don't know whether that shows any element of guilt or not, but that certainly disappointed me," added the Dubliner.
"It could have been a lot more serious injury. It was weird, it was one of those moments that you can see it happening. I knew I was in trouble from the moment I was up in the air.
"It was a matter of getting my head out of the way to make sure it wasn't the part of my body that took the impact on the ground.
"If you look back, you are hugely disappointed with a shoulder dislocation, but with hindsight, it could have been worse if I had gone down on my head."
Lions coach Sir Clive Woodward, who has opted to install Wales' Gareth Thomas as captain for the remainder of the tour, added: "I think the video tapes of the incident were conclusive. To me, there was plenty enough evidence.
"I am very disappointed the two players weren't even brought in to talk about it. You can still be cited and go to the hearing and be totally acquitted, but just to say nothing happened in that incident is, to me, an amazing decision to make."