This is a total guess and may not be accurate. Could the year have been 1974?
Gary Sheidi led BYU to the Fiesta Bowl, which was BYU's first ever bowl game. BYU may have won, but Sheidi went down with a serious shoulder injury. Fans may have rallied around the team with a welcoming parade despite the loss. Maybe the guy in the sling was Sheidi? Just a guess.