That summer Mokosak was selected in the seventh round of the NHL entry draft, 130th overall by the Hartford Whalers in 1981. Being just 18, he returned for his final two years of junior eligibility and while he improved his game from a personal standpoint, the Cougars were unable to advance to the national championship again.

Mokosak attended the Whalers training camp in the fall of 1983, but he was not ready to join the big club and was dispatched to the team's minor-league affiliate in Binghamton. He continued to patiently play in the minors but his chance to play for the Whalers in the NHL never transpired. Once his contractual obligations to the Whalers ended, he signed a free agent contract with the Detroit Red Wings in the summer of 1998. Although his tenure was not long with the organization, he did suit up for 41 games with the team over two seasons, picking up two assists, which was the extent of his career in the league.

He signed a one-year contract with the Boston Bruins in the summer of 1990 and another deal with the New York Rangers the following year, but played exclusively in the AHL for the remainder of his pro career with Adirondack, Maine and Binghamton of the AHL and finally the Phoenix Roadrunners of the IHL in 1992-93. Mokosak's older brother Carl was also an NHL player, suiting up for five different teams in the 1980s.

Courtesy of the Hockey Hall of Fame