Who cares if he's a walk-on or not? If he is the best player start him! I can see how it could be a recruiting issue, but maybe he was just underrecruited... or maybe he's REALLY developed... If he's the best player, start him - and give him a chance! If he doesn't pan out, fine, but there is no reason to have an anti-walkon bias when he is playing the best of available options.
The point is, Plummer has way better measurables. If he’s not beating O’Connell out, that means the coaches are failing when it comes to developing recruited talent. Ditto Thienemann and horvath. Graham looks lost so I have a hard time believing they couldn’t do better.