Bendtner is currently on loan at Sunderland from Arsenal but O'Neill believes that negotiations over a possible permanent deal will not take place until the summer.
The former Aston Villa manager told BBC Sport: "We haven't discussed it at all.
"It's a three-party affair. That was the way we said we would leave it anyway, until the end of the season."
Bendtner scored his eighth goal of the season during Sunderland's 2-2 draw with Bolton Wanderers on Saturday.