From MLB Power Pros Wiki

Character Background

Coach Stone is a character in Success Mode 2007. 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 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.