Marcus needs to score. Even though his minutes were limited against Georgia and Oklahoma State he also went 1-9 from the field and 0-5 from 3. After that just play decent defense and get a few rebounds. Honestly, I'm fairly confident that he'll do that consistently because he already has most his short career.
IMO the key for the rest of the season isn't so much Marcus as it is the other guys. I think his little deal is mostly over and we pretty much know what we're going to get. However, we don't always know what we'll get from Jevon, Hurt, and Westicles. Nino and Gip have been fairly consistent, but those other guys haven't. We've just got to have the majority playing well at the same time like we did in Norman and this team will win plenty more games. The question is how consistent that will happen.