O'Brien told BBC Radio Leeds: "I won't be surprised if they didn't offer me another contract.
"Although I feel I'm playing hard and well here I don't think my progress here will have any bearing on my future at Bolton."
The former Bradford, Newcastle and Republic of Ireland centre-back joined Bolton in 2007 and went on to make 68 Premier League starts for the Trotters.
However he had managed just three games for Owen Coyle's side this season before his move to Elland Road and his deal expires in the summer.
He has made seven appearances for Leeds, scoring once, and they have not lost in any of his games.
United chairman Ken Bates has already stated publicly that Leeds will do their best to keep O'Brien until at least the end of the season.
"On the one hand people say you're out of contract and things are rosy, but on the other I feel I've proved some people wrong with my performances here," he said.
"When I played at Bolton I suffered a few injuries and people start writing about you that you can't do it anymore.
I reckon it's no coincidence that our current unbeaten run is with Andy O'Brien at the heart of our defence
Sniffer-Alan1972
"My staying here will obviously be dictated by results and if I'm playing my part in good results then hopefully something can be sorted.
"I'm doing this for myself and for Leeds United because they are my employees.
"I'm grateful to be here and to Leeds for giving me the opportunity.
"We are on a good run and I'm just playing my small part in that.
"I'm just working hard to stay in the team and others are working hard to get into it, so that's a good recipe for success."
Source: BBC Sport
Source: BBC Sport