Tom Zupancic resigned on Friday as the Indianapolis Colts' senior vice president of sales and marketing, ending 27 years with the NFL franchise.

The reason behind the departure was not clear. In a written statement to Colts' business associates, Zupancic wrote, "It is with bittersweet feelings that I am announcing my retirement from the Indianapolis Colts organization ... I feel blessed to have worked for one of the premier organizations in the National Football League."

Zupancic and Colts officials did not return calls seeking comment.

In his statement, Zupancic wrote, "I leave you with the most passionate staff in the NFL. I am confident that you will continue to enjoy excellent service delivered with professionalism. It has been my honor to work with you, and I wish you continued success in your business and in our mutual pursuit of another World Championship."

Zupancic had been with the Colts since they relocated from Baltimore to Indianapolis in 1984. He served as the team's strength and conditioning coach until 1999, when he became director of business development.