The Tuesday decision by NFL owners to approve a 17th regular-season game means the Vikings will head west three times in 2021, and face the Chargers on the road for the second time in three years.
The scheduling quirk — for two opponents that ordinarily face each other once every four seasons — is due to the formula the league used to determine opponents for a 17th game. The NFL made its new regular-season game a non-conference contest, to be determined by a similar formula to the one the league had used to finalize each team's 15th and 16th regular-season games under the previous format.
According to the formula the league had used since 2002, each team had played the following games:
—6 games (3 home, 3 away) against three division opponents (for the Vikings: 2 games against the Bears, Lions and Packers each year).
—4 games (2 home, 2 away) against an entire division in its own conference (the Vikings play the entire NFC West in 2021, traveling to Arizona and San Francisco while playing host to Los Angeles and Seattle).
—4 games (2 home, 2 away) against an entire division in the opposite conference (the Vikings play the entire AFC North in 2021, traveling to Baltimore and Cincinnati while playing host to Cleveland and Pittsburgh).
—2 games (1 home, 1 away) against the other two divisions in its own conference, determined by which teams finished in the same place in the division the previous year (since the Vikings are already playing the entire NFC West this year and finished third in the NFC North last year, they'll play the third-place finishers in the NFC East and NFC South — at home against Dallas and on the road against Carolina).
The 17th game, then, means the Vikings will play an AFC team that finished in the same spot in a division other than the one they are already facing. The league started with the NFC North traveling to face the AFC West, meaning that division's third-place finisher (the Chargers) are on the Vikings' 2021 schedule.
It means the Vikings will play eight home games and nine road games this year, but the format will flip in 2022, giving them nine games at U.S. Bank Stadium against eight on the road. Next season, they're scheduled to play the entire AFC East, so their ninth home game will come against a team from one of the other three divisions (the West, North or South). Given the fact the Vikings are facing the AFC West this year, it stands to reason they'd begin a rotation that would have them playing a home game against a team from the AFC North or AFC South in 2022.
Their last trip to Los Angeles — a 39-10 win during which the Vikings forced seven turnovers — saw them play before droves of Vikings fans who'd traveled west to enjoy the California weather in December and take over the 25,000-seat soccer stadium the Chargers were temporarily calling home after their move from San Diego. This time, the Vikings will make their first trip to SoFi Stadium, site of Super Bowl LVI next February.
Or — in one final twist! — they could get sent abroad. The league reportedly plans to move four of the 16 new inter-conference matchups to international sites, though the Chargers gave up home games in 2018 and 2019 to play in London and Mexico City, respectively, and might not be asked to surrender a home game again for several years.