Question: Who is the founder, owner and president of the Boras Corporation who's clients include an American professional baseball center fielder for the New York Yankees who  played in MLB for the Boston Red Sox from 2007 through 2013, and joined the Yankees before the 2014 season ?
Sentence (from "Jacoby Ellsbury"): He played in MLB for the Boston Red Sox from 2007 through 2013, and joined the Yankees before the 2014 season.
Relevant evidence: No