While the former Republic of Ireland centre-half enjoyed immediate success on his first start at Elland Road - helping Simon Grayson's side to a 4-1 victory over Scunthorpe United - he is reluctant to make assumptions about his future.
"I've never manipulated a situation," O'Brien said, "and I'm not going to do that now.
"The way I see it, you're with a club and you play hard to stay in their team. If you're not in the team, you fight hard to get into it.
"I'm here for a month and I'm out of contract with Bolton at the end of the season. They're the only two things I know for sure."