"Bolton Have Close-Knit Dressing-Room"
"I have no regrets about coming here in the slightest," the defender told the Manchester Evening News.
"I said when I came here that I was grateful for the opportunity and I'm enjoying my football now, more than I ever have done.
"Once you experience the other side of it, when you are playing in the reserves every week and not getting selected for the first team, it makes it more enjoyable when you do."
"I have born the brunt of opinions before when someone brings you in only for another to take over," he explained.
"But the principles are the same. If you are in the team you work hard to stay there.
"If you are not then you work hard to keep pushing those who are in it."
O'Brien added: "We have a close-knit dressing-room and we have got to stick together to get ourselves out of this situation."