Although he said GOP senators have not decided to fight any Obama pick to replace retiring Justice David Souter, in his appearance on "Fox News Sunday" the Kentucky Republican did say that, "Under the rules of the Senate, all things are possible."
McConnell said Obama's pick will ultimately determine whether Republicans seek to block the nomination.
"I think it is way premature to be predicting what kind of procedural moves will be taken when we haven't even seen the nomination yet," McConnell said.
McConnell's comments came as Senate Republicans last week blocked confirmation of David Hayes, an Obama Interior Department nominee. The GOP blocked Hayes amid a dispute over oil and gas development on federal lands.