I just had a look at the Optimal Planning Solutions website, and it seems to have largely cornered the market on scheduling for professional sports leagues. In terms of North American clients, these include MLB, MLS, and NFL, while overseas clients include Australian Football League, National Rugby League, and Scottish Premier League.
I wonder if it might be worth a try for OOTP to contact them to see if it might be possible to have a stripped down, simplified schedule creation software version made for use by the game, particularly since OOTP is associated with MLB and is a licensee.
ETA:
Just found this article on SI.com about the creation of the NFL's 2017 schedule.