In 1967, Seelbach played collegiate summer baseball with the Orleans Cardinals of the Cape Cod Baseball League, where he was named a league all-star and tossed a no-hitter against a Chatham team that included Thurman Munson.

On April 20, 1972, Seelbach combined with Tom Timmermann for a two-hitter but lost to the Baltimore Orioles, 1–0, on a home run by Paul Blair.

Seelbach was also on the mound when the Tigers clinched the American League East championship on October 3, 1972.

Seelbach set down the Boston Red Sox 1-2-3 in the 9th inning to clinch the AL East title, as the game ended on a Ben Oglivie fly ball caught by Al Kaline in right field.

A shoulder injury the next year ended his appearance in the league.