Sponsored Content SportsEngine, a brand from NBC Sports Next is the leading provider of Sport Relationship Management (SRM) software, empowering athletes, parents, coaches, and sports organization administrators with tools and services to manage their organizations and sports lives. Read SportsEngine stories Mark McGwire Sets Rookie HR Record May 20, 2021 | 0 minutes, 25 seconds read On this day, in 1989 Oakland's Mark McGwire set a rookie HR record at 39, he ended his rookie season in the MLB with 49 home runs. August 14, 1989 Sport: Baseball Trivia sports in this article Baseball tags in this article Fan On This Day SportsEngine