The beautiful game is about to get a mirror.

Starting Saturday, Major League Soccer is implementing the Video Assistant Referee, or VAR, in every match, including Minnesota United’s 7 p.m. match against the Seattle Sounders FC at TCF Bank Stadium.

The video person will sit in a booth at the stadium and have access to all available broadcast angles to “check all plays for potential clear and obvious errors or serious missed incidents in four game-changing situations – goals, penalty decisions, direct red cards and cases of mistaken identity,” according to the league.

If a review is required, the VAR will alert the referee on the field, who will make a box gesture with his hands to indicate the VAR is examining a possible error. All final calls will lie with the head referee.

The VAR was showcased on an international level during this summer's Confederations Cup in Russia and the Under-20 World Cup in South Korea, with mixed results.

MLS has been preparing for this moment for three years, determined to get it right.

"The idea is minimum interference for maximum benefit," said veteran referee Howard Webb, who is overseeing the league's implementation of video replay. "We're not trying to change the way the game is played. We're trying to enhance it. We're trying to make it fairer. We're trying to make sure the outcomes are right."

United coach Adrian Heath joked he’d have a more informed opinion about VAR after Saturday’s match, depending on how many decisions went for or against his team.

“I think it’s a very difficult situation,” Heath said. “I think it’s going to be tough for the supporters to understand, but anything that gets the big decisions right, I think we have to look at it now because I think maybe 10, 12 years ago, 15 years ago, it would have taken too long. But now within five seconds of the incident happening, the TV knows that was outside the box or that was a handball.

“I think everybody’s on board to give it a go and give it the best opportunity to succeed.”

Heath recalled Frank Lampard’s disallowed goal from the 2010 World Cup that would have tied the match for England against Germany, had the referee not called it off thinking the rebounded ball from the crossbar didn’t cross the goal line. England ended up losing 4-1, and that decision “completely” changed the match, he said.

United center-back Michael Boxall thought back to French star Thierry Henry’s infamous handball that ended up keeping Ireland out of the 2010 World Cup and said if VAR can prevent instances like that, it will only be good for the sport, despite some purists who believe soccer should be free-flowing and unblemished by video reviews.

Boxall has already experienced VAR playing with New Zealand in this summer’s Confederations Cup in Russia. He received a “pretty big introduction” to it in his team’s 2-1 loss to Mexico. Boxall was at the center of a stoppage time fight between the two teams that his bad tackle started.

“I maybe could have been sent off, but three or four of the best officials in the world apparently reviewed it several times. And if that’s not deemed a red card, then there could be a lot of injuries,” Boxall said. “So obviously, it’s not a perfect system. And I don’t expect it to be spot on right away. But I think as a defender, you don’t want to get a goal scored against you that clearly shouldn’t be allowed.”

One of the other failings Boxall pointed out happened in New Zealand’s 2-0 loss to Russia. Boxall said there were a few close offside calls that he knew were offside when he re-watched them after the match. But the linesman let the play continue because if it ended in a goal, VAR could review it. But if it were to go out for a corner and the offside team scored from the corner, then nothing could be done.

In the end, VAR is still a bit ambiguous and comes down to that person’s opinion. Heath said of the two big VAR decisions in the Confederations Cup, he disagreed with both, so it’s still “arbitrary.”

Heath pointed out there are bound to be some awkward situations, such as a no-penalty on one end of the pitch and then quick score on the other end, only for VAR to pull back play to before the goal to award the uncalled penalty.

“That’s going to be OK in America. I wouldn’t like to do that one in South America,” Heath said. “Boca Juniors, River Plate. I wouldn’t like to be the referee who had to make that decision.”

Australia's top-flight A-League used a version of video review on trial earlier this year, and the South Korean K-League Classic began working with it in July.

At least two other top-tier leagues will add a VAR soon. The German Bundesliga will debut video replay for the season opener between Bayern Munich and Bayer Leverkusen on Aug. 18. The Italian Serie A will also introduce its version after adding goal-line technology last season.

For now, all eyes are on MLS and how it rolls out the VAR protocol. The league has not publicly stated its investment in video review.

"We've seen some really big players — and make no mistake about it MLS is a big player in the global soccer world — make the decision to take it on board, and undoubtedly we will be watched by the leagues that haven't made the decision as well as the leagues that are doing it," Webb said. "We are confident with our extensive preparation that what they'll see will encourage them to do the same thing."

Webb serves as manager of video assistant referee operations for the Professional Referee Organization, which oversees on-field officials in the U.S. and Canada. He's got the credentials: He was a Premier League referee from 2003-14, and also worked the Champions League and World Cup finals in 2010. He also served as director of referees for the Saudi Arabian Football Federation.

Soccer's rule-making body, the International Football Association Board, approved trials of video technology in March 2016. Internationally, live experiments are taking place in about 20 competitions this year, including the recent Confederations Cup, considered a test for the 2018 World Cup.

Implementation at the Confederations Cup drew criticism because of slow reviews that seemed to confuse players, coaches and fans. But FIFA concluded that video replay helped referees overturn six "game-changing decisions." Calls made in 29 additional "major incidents" were confirmed correct on review.

"What fans have been waiting for over so many years is finally happening. This is a milestone tournament. Video Assistant Refereeing is the future of modern football." FIFA President Gianni Infantino said after seeing the VAR at work in early-round matches in Russia.

While MLS is considered something of a pioneer with the program at the professional level, the NCAA successfully used video replay dozens of times last season. A rules change last year allowed video replay in three situations: goals, player identification for disciplinary reasons, and to identify players involved in fights. Schools are allowed to use whatever equipment they see fit.

The technology was used in the men's College Cup final between Stanford and Wake Forest.

Critics point mainly to issues involving communication because fans, players and coaches are unable to see what is going on while in the stadium. Some have suggested that video review be adapted to show what the refs are looking at on video scoreboards — like other leagues, including the NBA.

Webb is pragmatic in understanding that the VAR protocol may have to be adapted. But the time has clearly come — and the MLS can lead the way, he said.

"Every time there's a big controversy in a game we have the same conversation: Why don't we have video technology? Why can't we use replays? Why can't we bring the game up to date with the way other sports have used the technology?" he said. "It is a challenge in soccer because of how the game is played, that's why it's taken a lot of training and a lot of preparation."

The Associated Press contributed to this report.