The 23-year-old flanker - who has made just one appearance for Ireland, in 2010 against Australia - impressed in Leinster's 28-25 victory over Glasgow Warriors on Saturday night.
Ruddock scored a late try with Irish teammate Ian Madigan also impressing with a 13-point haul - timely given Jonathan Sexton's battle to overcome an injured thumb.
But when pressed on Ruddock, who has struggled with injuries over recent seasons, O'Connor says he offers Ireland head coach Joe Schmidt an option ahead of their RBS 6 Nations clash with Italy this weekend.
"He's in the Irish set-up as the next best six I think," O'Connor said.
"I remember watching Rhys a couple of years ago and thought he would have had a massive future in the game and injuries and all sorts of other things kept him out of the limelight a bit.
"He's just been very, very consistent for us, he carries the ball, he's a great lineout option and he has a massive work rate. His impacts on the game are becoming greater and greater."