It took a while for the Vikings to get comfortable at TCF Bank Stadium, their two-year temporary home. But by the end of last season, Mike Zimmer's rugged, hard-hitting bunch looked like a team that belonged in the great outdoors.
The temperature at kickoff last Dec. 27 was 13 degrees when the Vikings hosted the New York Giants on the University of Minnesota's campus in prime time. As Giants quarterback Eli Manning reluctantly jogged out to the huddle with his hands stuffed into the hand-warmer strapped around his waist, he looked like a man in a bathrobe hurrying to retrieve his Sunday paper from a snowbank.
The Vikings sacked Manning four times and flustered him into throwing three interceptions, one of which they brought back for a touchdown. Running back Adrian Peterson bullied his way to 104 rushing yards and a touchdown before stepping aside for Jerick McKinnon, who tallied 89 yards and two more scores.
The Giants, eliminated from playoff contention the previous day, looked like a team longing for a warm, safe bus ride back to the airport. The Vikings, meanwhile, clinched a postseason berth with a dominant 32-point win.
Sunday, when the Vikings play their first game at the new U.S. Bank Stadium, a preseason exhibition against the San Diego Chargers, the billion-dollar venue's thermostat will be set at around 72 degrees. There might be a slight breeze if the Vikings open up those giant glass doors. And they definitely won't need any heated coils to keep the fast-track turf inside the stadium from freezing.
But don't assume that means the Vikings suddenly will become a "finesse" team.
"I don't think that's something we'd want to be called, especially on the defensive side," Pro Bowl safety Harrison Smith said. "We want to be tough, physical and play our game, and it doesn't matter where we play."
As long as Zimmer is the head coach in Minnesota, the Vikings are going to attack visiting quarterbacks and attempt to punish their opponents on the ground. But the move to U.S. Bank Stadium will impact them, in some ways more obvious than others. They no longer have those Minnesota winters on their side, but they will remember how to use the great indoors to their advantage again.
The offense
During their Metrodome days, which spanned from 1982 to 2013, the Vikings had some high-flying offenses, none more thrilling than Randy Moss and their record-setting group in 1998 and Brett Favre's magical run in 2009.
Teddy Bridgewater isn't going to magically morph into a 4,000-yard passer this season. But the third-year quarterback, whose arm isn't the NFL's strongest but who has more than enough zip to get by, should be even more efficient inside.
Over the past decade, NFL teams have averaged 23.5 points per game in domed stadiums vs. 21.8 points outdoors, according to Pro Football Reference, which did not include stadiums with retractable roofs in its calculations. When indoors, quarterbacks averaged more yards per pass (6.9 to 6.5) and offenses more yards per play overall (5.6 to 5.3) than when operating outside.
In four career games indoors, which is a pretty small sample size, Bridgewater completed 71.0 percent of his throws for an average of 238.8 passing yards per game. Outdoors, he completed 63.6 percent for an average of 202.5 yards. His passer rating indoors (91.3) was slightly better than outdoors (85.2).
"You don't have to worry about any wind factors or anything like that," said Bridgewater, who is 15-9 as a starter outside vs. 2-2 in domes. "I think it's a set temperature every time you play indoors, so it's going to be great."
Running back Adrian Peterson, a first-team All-Pro in 2015, should also benefit. Peterson has played 62 games indoors in his career and 52 outdoors. He has averaged 5.1 yards per carry in domes vs. 4.8 in outdoor stadiums.
Peterson said he prefers running on natural grass, and he was surprised when a reporter told him he had actually put up better numbers indoors on the turf.
"Is that right?" he said. "Good thing we've got turf inside our stadium, huh?"
The defense
Of course, the controlled climate of U.S. Bank Stadium also will make completing passes easier for opposing quarterbacks such as former MVP Aaron Rodgers, whose Green Bay Packers are the visitors for the home opener Sept. 18.
The Vikings are imploring fans to pump up the crowd noise to Metrodome levels when opponents have the ball to neutralize any advantage they might have.
"If you're indoors and it's loud, I think that's a big advantage for your pass rush because [their offense is] going on silent cadence" and is unable to use a hard count, Zimmer said. "If it's turf, you're quicker, and if you've got really good edge rushers it puts stress on their offensive tackles."
In other words, Rodgers can't put up big passing numbers if he's on his back.
The statistics back up Zimmer, who calls the defense for one of the league's fastest and most athletic units. Since 2006, defenses playing their home games indoors averaged 2.40 sacks per game, according to Pro Football Reference, vs. 2.33 outdoors.
During the Metrodome years, the Vikings had the NFL's second-highest differential between home (.644) and road (.404) winning percentages, according to ESPN Stats and Information.
Zimmer will miss the frozen tundra of TCF Bank Stadium, though. In the Zimmer era, the Vikings are 4-1 in games during which it was below 30 degrees. The only loss was the 10-9 playoff heartbreaker against the Seattle Seahawks in January. They allowed 17 or fewer points in all five games. In June, Zimmer said — seemingly joking, but perhaps not — that he wished the doors at the new place would still be open in December.
"Hopefully we can turn on the AC" at U.S. Bank Stadium, Smith said with a laugh. The safety's grin quickly disappeared, though, and he insisted the steely attitude that was forged in freezing games like the Giants beatdown isn't going anywhere.
"People aren't scared of much in the NFL, but when they turn on our tape, they know they're going to be in for a long day — guys hitting and all 11 men running to the ball," he said. "So that's really our mind-set, whether it is hot or cold."
Special teams
The move back indoors might have the biggest impact on special teams, where wind can't blow frozen K-balls wide of the uprights or out of bounds.
"It'll help our returners, it'll help our kicker, our punter," special teams coordinator Mike Priefer said. "And unfortunately it's going to help the opposing team, too."
Surprisingly, though, since 2006 the difference in field-goal success rate when kicking indoors vs. outdoors has not been as stark as expected. According to Pro Football Reference, it is just 0.5 percent, the equivalent of one more football splitting the uprights in every 200 kicks.
But kicker Blair Walsh has been significantly more successful indoors during his four-year career. He has made 87 percent of his field-goal attempts in domes, including going a perfect 16-for-16 at the Metrodome as a rookie. Outdoors, Walsh has made only 82.5 percent of his field-goal tries, though in 2015 he was kicking at a respectable 87.5 percent clip before his infamous playoff miss.
"Going back inside, you wake up on Sunday morning and you don't care what the weather's like," Walsh said. "You just go inside and try to do what you do."
Leaguewide, punting inside has resulted in only an extra 0.07 yards per punt since 2006. But four of the top five punters in net punting average last season played their home games in a dome or a stadium with a retractable roof. The Vikings are hoping that punting indoors will help Jeff Locke display the kind of consistency they haven't yet seen from him after drafting him in 2013.
While Friday was the first time the whole team practiced at U.S. Bank Stadium, the Vikings sent Walsh, Locke and long snapper Kevin McDermott down to the new stadium twice this spring so they could get acclimated to the new venue.
"We went in [to the new stadium] and did our homework," Priefer said. "I'll send them down there during the season as well just to get used to the sightlines, and the field itself and the turf itself, and make it a home-field advantage for us."