"There are, I hope, some Test places to play for," he said.
"Being realistic, I suppose it would be about four or five, and people are aware of it.
"The most important thing, though, is that we make a statement as a team and there will be certain individuals who may benefit, but who knows who those people are at this minute.
"Having said that, if we don't perform as a team then none of us have a chance.
"What I have learnt in my career is that the collective is far more important than the individual, but individuals do benefit as a result of the collective."
O'Gara becomes the Lions fifth skipper on tour - he follows Paul O'Connell, Brian O'Driscoll, Phil Vickery and Donncha O'Callaghan - and is keen to put pressure on current Test fly-half Stephen Jones.
"I've got to keep the pressure on Stephen, and that has to be the goal on Tuesday night for as long as I'm playing," he added.
"Of course, I want to run out on Saturday to start the Test, but now I have this to think about, this huge honour of captaining the Lions, so my focus is probably taken a bit from that.
"It's a huge bonus and a very big day for me."