"I got a good feel for the place and it was one of those clubs where young lads would be given a chance.
"There were a few clubs interested and a lot of my friends, who were as good as me, went to the bigger clubs. But they've never had a chance.
"When I came here, Kevin Nolan was playing in the first team and had come through the academy. When I signed, Nicky was on the verge of the first team."
"Obviously, it was a huge decision," O'Brien said. "My mam and my dad and my older brothers gave me a lot of good advice. They said this was the right club for me and the way things are going for me now, the choice was obviously the right one."
Meanwhile, Bolton manager Sam Allardyce was absent as the squad left Manchester airport ahead of the UEFA Cup clash against Marseille.
Allardyce, who is suffering from a chest infection is expected to arrive in France on Thursday with assistant manager Sammy Lee in charge in the meantime.