Two more things I noticed about him yesterday. There was one point late in the game where Nixon started off 2-0 on one of their batters, and Mershon went halfway to the mound and (I'm assuming) had a little pep talk with him. Camera's didn't deliberately show it and the announcers didn't mention it, but that little bit just shows the leader in him.
And on the double play that ended the game, he (and Larry) absolutely sold the runner with a deke move to second as if it were a ground ball to help hold him up and allow Clark to double him off. The kid's smart, plays situational ball, and is always helping even when the ball isn't coming to him.