BYU lost their four Sept games (Utah, Mich St, Ariz St and Minn) when the Big 10 and Pac 12 went to conference only scheduling as well as their last game of the season (Nov 28) with Stanford.
Now that the SEC is playing conference only games, they've lost a sixth game - Missouri (Oct 10). After the B10 and P12 announcements, they reportedly were filling their opening game of the season with Alabama, but that's now gone.
Now that the P5 conferences except the B12 have decided, BYU's remaining schedule include five Group 5 games.
Three are against Mountain West teams - Utah State (Oct. 2), Boise State (Nov. 6) and San Diego State (Nov. 14)
One is against a MAC team - Northern Illinois (Oct. 24)
One is against an American Athletic Conference - Houston (Oct. 16)
Group 5 conferences are expected to announce their schedules soon. Should those follow the conference only scheduling, BYU would be left with only one game against Northern Alabama.