The Minnesota Vikings, winners of one playoff game since the 2004 season, and the Samsonite Rams, winners of zero playoff games since the 2004 season, will play a big game at U.S. Bank Stadium on Sunday. This is a testament to the importance of excellent coaching in the NFL.

Former Rams coach Jeff Fisher built a strong reputation around the league when he coached the Tennessee Titans. There is no reason to revise history and pretend, based on his late-career failures, that he was always overmatched. He won 13 games in consecutive seasons and came within a yard of winning a Super Bowl with a franchise that has otherwise been the definition of mediocrity.

Fisher was an outstanding coach once upon a time. He was not with the Rams, with whom he built a 31-45-1 record with zero playoff appearances.

Now we know to what extent Fisher acted like a depressant on an entire franchise. Sean McVay, 31, replaced Fisher and in his first season as a head coach is 7-2 with virtually the same roster that finished 4-12 last year. A year after the Rams scored 224 points and finished dead last in the league in scoring offense, they have scored 296 points in nine games and rank first.

Under McVay, quarterback Jared Goff, feared to be a bust last season, is playing like young Dan Marino, and receiver Robert Woods, who has never reached 700 receiving yards in a season, needs only 78 yards Sunday to reach that modest milestone. Unless the Rams collapse, McVay will be the NFL coach of the year.

Vikings coach Mike Zimmer and offensive coordinator Pat Shurmur have also demonstrated the power of coaching expertise. In Zimmer's first season, the Vikings' defensive ranking improved from 31 to 14. Last year, the defense ranked third in the league in yards allowed. Currently, the Vikings rank fourth in that category.

Under Zimmer, who is capable of teaching specific techniques as well as constructing effective game plans, Xavier Rhodes has become one of the league's best cornerbacks, Trae Waynes has evolved into a trusted player and Everson Griffen has become one of the league's best pass rushers.

Just as important, seeming flaws, such as the safety spot opposite Harrison Smith, have become less glaring. Andrew Sendejo, once considered a placeholder, performs like a solid veteran.

Zimmer sometimes struggles to be an effective team spokesman, but there has never been reason to question his expertise or work ethic.

Shurmur's emergence as one of the most important figures in the Vikings organization is almost as stunning as McVay's rise. Always considered a capable coach, he built a record of 9-23 as head coach of the Cleveland Browns in 2011-2012. That got him fired. It should have landed him in the franchise's Hall of Fame, considering current coach Hue Jackson is 1-24.

The Vikings are playing the third-most accomplished quarterback in the organization, are without the running back who promised to be their most dynamic playmaker, are getting mere inches of yards after contact from supposed workhorse Latavius Murray and are playing behind offensive linemen who barely know each other. They rank ninth in the NFL in yards per game and former undrafted free agent Adam Thielen ranks third in the league in receiving yards.

Shurmur's work as an offensive coordinator should give him a chance to become a head coach again. Perhaps no Vikings coordinator has done so much with so little since Tony Dungy ran the defense in the '90s.

The essence of coaching is improving individuals to benefit the team. Operating in a league that attempts to create parity with a salary cap and an inverse draft order, McVay, Zimmer and Shurmur are proving that the NFL's most important free agents are almost always coaches.

Jim Souhan's podcast can be heard at MNSPN.com. Twitter: @SouhanStrib. jsouhan@startribune.com