The loss of Tucson Roadrunners coach Mike Van Ryn after one season — one AHL division-championship season — is disappointing but not a surprise. Minor-league coaches are as transient as minor-league ballplayers. In the first 30 years of the Tucson Toros, a Pacific Coast League franchise, the Toros had six one-season managers: Billy Adair, Larry Sherry, Hank Aguirre, Carlos Alfonso, Tim Tolman and Tim Ireland. Van Ryn joined the NHL’s St. Louis Blues as an assistant coach.