In the Flames' Stanley Cup championship season of 1988–89, Peplinski scored 38 points in 79 games, and appeared in 20 more games in the 1989 Stanley Cup Playoffs. Prior to the sixth game of the final against the Montreal Canadiens, head coach Terry Crisp wanted to insert McDonald, who was expected to retire following the season, into the lineup for the possible clinching game. As a result, Peplinski was scratched from the line-up and watched as the team won the championship. He came onto the ice to accept the trophy with McDonald and alternate captain Tim Hunter.