Gruhl began a lengthy career in the International Hockey League with the 1979-80 season, skating with the Saginaw Gears, and quickly established himself as a goal scorer. He led the Gears in scoring with 53 goals and 93 points in 75 games. A second season in Saginaw saw similar results. In the postseason, the Gears captured the Turner Cup with a sweep of the Kalamazoo Wings.

As part of the Los Angeles Kings organization, Gruhl was assigned to the New Haven Nighthawks of the American Hockey League for two seasons, during which he scored 28 and 25 goals, as well as making his much hoped-for NHL debut. Called up by the Kings, Gruhl played in seven NHL games in 1981-82, and scored a pair of goals and an assist. In 1982-83 he again saw action in Los Angeles, during which he added two more assists over seven games.

It was back to the IHL and Michigan for the 1983-84 season, as Gruhl joined the Muskegon Mohawks. There, he led the team in scoring with 40 goals and 96 points. With an ownership change, the franchise changed it’s name to the Muskegon Lumberjacks for the 1984-85 season. Gruhl had an outstanding year, scoring 62 goals and 64 assists for 126 points, all career bests. He placed second in the league scoring race and was named the IHL’s MVP. In total, Gruhl anchored left wing for seven seasons in Muskegon between 1983-1990. In 1992, the Muskegon IHL franchise was moved to Cleveland.

Gruhl spent five more years in the “I”, splitting time between Fort Wayne, Milwaukee, and Kalamazoo. When he left the IHL, he had combined for more goals between the regular season and playoffs than any other player in league history.

He concluded his 17-year professional hockey career in 1995-96 as a player and coach for Richmond of the ECHL, followed by a game with the Baltimore Bandits of the AHL, and a pair of contests with Fort Wayne before hanging up the skates.