I don't think Michael Corleone would have withdrawn if Novak wasn't in the other half.
I think he basically committed fully and physically to protecting game piece Kyrgios from having to expend energy on game piece Fritz, knowing game piece Norrie will play his part in taking the Joker to at least 4, possibly 5 sets, so that game piece Kyrgios, fresh as a daisy, has a reasonable crack at keeping the Joker two squares behind Michael Corleone in the race for the all time number count. The only picture Michael cares about now is the big picture.
It's not a withdrawal Sonny. It's strictly business.