O'Connor ended a three month layoff by appearing in his team's defeat of Leicester earlier in December but is facing another six weeks on the sidelines.
The former Liverpool youngster sustained a dislocated and ruptured shoulder joint during a training session five days after the win.
But O'Connor, 20, is determined not to let the injury get the better of him, telling the club's official website: "You just have to keep going.
"I've had setbacks before. I think I am used to them. Now I think I've got over a hurdle before, proved someone wrong before and I'll do it again.
"The knocks have toughened me up. I think the setbacks I've had have made me a better player. To get back in the team recently just makes me hungrier to do it again when I'm fit."