The Goalie

The goalie of the varsity soccer team is a senior who has played soccer for 4 years. As a junior he was asked by the coach to play goalie; not because of his great skill, but because he was the best player available. Now, as the season begins the coach observes a freshman who is not only an excellent scorer, but has replaced the injured goalie on the JV team and is an excellent player. Does the coach replace the senior with the freshmen - who is obviously more skilled/talented - as the varsity soccer player? Why or why not