GENEVA (AP) The goal of helping referees with video review to make decisions at the 2018 World Cup has been facing key tests at FIFA headquarters.
Two systems among the 11 in talks to win the World Cup contract were undergoing trials this week during training sessions with Europe's candidates to referee in Russia.
An idea met with a skeptical response when then-FIFA President Sepp Blatter presented it in 2014 has support from his successor, Gianni Infantino - even if Blatter's idea of NFL-style challenges by coaches looks unlikely to survive.
It is not certain that video assistance referees, or VARs, will be approved in time for the World Cup.
Still, history was made on Wednesday with a first significant intervention by video review at a Dutch Cup match. Willem II player Anouar Kali was sent off for fouling an Ajax opponent one minute after the referee initially showed a yellow card.
Here is how FIFA is moving to give top-level referees the kind of help that is standard in American sports leagues:
FIFA wants video review only for potential ''clear errors'' in four situations: goals being scored, penalties being awarded, players being sent off and cases of mistaken identity.
It needs a technology system to help VARs and the referee communicate quickly without spoiling the game's flow.
Massimo Busacca, FIFA's director of refereeing, believes it should take ''not take more than five, six seconds'' to review an incident.
''If we need one (camera) angle more, of course it can take two seconds more,'' Busacca told The Associated Press.
In most situations, play has naturally stopped and review time will not disrupt the flow.
All involved agree that calling back play to impose a decision not initially taken is the biggest challenge for FIFA and its rule-making panel, known as IFAB, which must give final approval.
THE TECHNOLOGY SYSTEM
The DreamCatcher system developed by Evertz Microsystems of Burlington, Ontario is among FIFA's options. It has already been proven in NFL, NBA, MLB and NHL games.
This week at FIFA, two DreamCatcher operators worked in a windowless portable cabin next to the hedges lining the soccer body's compound.
Two banks of screens - each to be monitored by one of two VARs, helped by a technician - take feeds from cameras around the artificial turf pitch that flanks FIFA's offices.
The largest wide-screen TV above the desk shows a live game feed. Two smaller screens at desk level show several angles of the action at a slight delay, allowing the VARs to take a quick glance at an incident. The VAR can ask to zoom in anywhere on the split-screen images. Each World Cup match has at least 30 cameras, but too many angles can slow a decision.
Though the NBA and MLB centralize review operations in one location, FIFA would likely want each VAR team in a truck or booth at each of the 12 stadiums in Russia.
FIFA had set a two-year timetable and wants a decision by IFAB by March 2018.
''This has been the most thorough review of the leagues we have worked with,'' DreamCatcher project manager Nima Malekmanesh said.
THE REFEREES' BOSS
Six seconds. In that time, Busacca wants his officials to know if they must change a clear mistake.
That will require expert analysis and communication skills from the VAR, who Busacca believes should also be a FIFA-list official.
''Absolutely. If he is not the same level, how can he change the decision of the referee?'' said Busacca, who suggests video review could be a rarity at World Cups with only the best referees taken from each continent.
''If you have a top referee, one situation every four or five games,'' he said.
Busacca insists video review cannot compromise the ''personality and football understanding'' of his officials, and he is no fan of letting coaches challenge decisions.
''Never lose the authority of referees, never take it out,'' he said.
Bjorn Kuipers supports video review within clear limits.
''You need a VAR which you can trust,'' said the referee from the Netherlands. ''If you don't have a VAR on the same level, it will be difficult.''
He foresees the two video reviewers joining a referee's two assistants and fourth official as part of a regular match team from the same country, speaking their native language.
''The communication has to be very clear, very short,'' said Kuipers, who worked the 2014 Champions League final before going to the World Cup in Brazil. ''We have 10 seconds or 12 seconds if we want but it's not good for the game.''
Kuipers was granted 10 seconds earlier this month when Italy hosted France in Bari, and he made a key video-assisted decision to show France defender Djibril Sidibe only a yellow card for fouling Daniele De Rossi. The Italy midfielder's teammates wanted a red card.
''Players like it when they got confirmation,'' Kuipers said, referring to that outcome.
THE FIFA MANAGER
As FIFA's lead official for technological innovation, Johannes Holzmueller oversaw the process of approving goal-line technology and picking the GoalRef system for the 2014 World Cup.
Holzmueller visited the U.S. in February to hear from pro leagues about their experiences with video review.
The 11 contenders in talks with FIFA also include American firm XOS Digital and Hawk-Eye, the British system used in Amsterdam on Wednesday.
The technology works, and FIFA must find ''a clear protocol'' for feeding information to referees, Holzmueller said.
Coaches' challenges could lead to stoppages to tactical reasons, and requiring referees to check images on a tablet computer also appears to be slow.
''We have to look at, `Does it improve the game and not just refereeing?''' Holzmueller said.