The Irish international is part of a 45-man Lions squad bidding to become only the second tour party to win a series against New Zealand in 11 attempts.
As ever, competition for a crack at Graham Henry's men is fierce, and none more so than in the second row, where O'Connell has four genuine rivals for a spot in the Lions Test engine room.
"It will be unbelievably hard to get in the Test side. Malcolm O'Kelly is in great shape, Donncha O'Callaghan is looking strong while Danny Grewcock and Ben Kay have won the World Cup. There are five good guys going for two positions," he said.
O'Callaghan's inclusion in the 45-strong party may have raised a few eyebrows, given he has won just 16 caps for Ireland, 13 of them as a replacement, but O'Connell is backing his Munster colleague to make an impact.
"Maybe people were surprised when Donncha was named in the squad, but it's unbelievable how fit and strong he is.
"I think he just needs a chance at international level. He had a storming game against Argentina and I'm expecting big things from him," he said.