The Black cats have already picked up Kader Mangane on loan from Al-Hilal as well as French midfielder Alfred N'Diaye from Bursaspor but O'Neill has indicated that he is looking for more inclusions before the end of January.
"I'm loathe to say we've got momentum going, but we've won four of the last seven and tonight we want to remain in the FA Cup," he told the Sunderland Echo ahead of tonight's FA Cup third round replay with Bolton.
"On February 1, whatever you've got left, that's it and we're still short here on players.
"Every side has had their injuries this season so we want to make some provisions for those things happening to us.
"They will be inevitable over the next few months."