From MLB Power Pros Wiki

Coach Stone is an NPC character in Success Mode 2007. He is a coach for Powerful Tulips and the man who decides whether or not the Main Character and Marvin are strong enough to play as the team's regulars.

Character Background

A Hall of Famer and former major league manager known for his iron fist, Stone had left baseball after his team lost a World Series.^[1] Rudy Fox arranges for him to coach the Powerful Tulips.

Stone talks only in grunts and mumbles, making translation only possible through Becky. His coaching skill is top notch though, as noted by Milton after he arrives.

Coach Stone's evaluation of the player will determine whether or not he will play in tournament games. To max out his evaluation, it is recommend to train as much as possible in the category that he is moderating.