Shearer limped off during the first half after adding an ankle injury to his head and hand problems, and although he has avoided serious injury he will need a couple of weeks rest.
"The doctor has seen the ankle and, while it does not look as though anything is broken, I will not play again this season," he confirmed.
O’Brien broke his nose for the second time this season, the first was against Inter, and despite Sir Bobby seeing the funny side he will also sit out the final two games.
"He already had a horrendous nose when it was right - you want to see it now," joked Sir Bobby.
"We're looking on the internet to try to find a nose shop!
"He's got a horrendous nose, poor lad. It's massive, it's black and blue, it’s awful.
"We couldn't stop it bleeding and we knew it was broken, so we took him off. It was never going to stop bleeding."