TORONTO -- Blue Jays reliever Dirk Hayhurst underwent surgery to repair fraying in the labrum of his right shoulder on Friday, and he is expected to be sidelined for most of the upcoming season. Hayhurst was initially in the running for a spot in the bullpen this spring.

Hayhurst, 28, injured his shoulder this winter while preparing for the upcoming season and will be out for at least four to six months. The operation -- originally described as an exploratory procedure -- was performed by Dr. Schickendantz in Cleveland.

The Jays signed Hayhurst as a Minor League free agent shortly before Spring Training last season, and he spent a majority of the year with Triple-A Las Vegas, posting a 3.75 ERA over 25 games. Over 15 games with the Blue Jays, Hayhurst fashioned a 2.78 ERA with 13 strikeouts and two walks over 22 2/3 innings.

That showing had Hayhurst in a good position to compete for a bullpen job in what is expected to be a wide-open race for a handful of vacancies this spring. The injury is an unfortunate development for Hayhurst, who is the author of the book, "The Bullpen Gospels: Major League Dreams of a Minor League Veteran," which is scheduled to be released on March 30.