The chairman of FIFA’s referees committee, Pierluigi Collina, says assistant World Cup referees have been advised to avoid flagging close offside calls during potential goal-scoring opportunities and leave them for video assistant refereeing (VAR) to decide.

“If you see some assistant referee not raising the flag, it’s not because he’s making mistakes,” Collina told The Guardian. “It’s because he’s respected the instruction to keep the flag down. They were told to keep the flag down when there is a tight offside incident and there could be a very promising attack or a goal-scoring opportunity because, if the assistant referee raises the flag, then everything is finished.”

There will reportedly be 13 referees officiating exclusively watching the control screens in the video operations room.  On those plays that require the use of VAR, fans inside the stadiums will be shown clips of the play under revision, but only once the referee has made his decision and play has restarted.

Collina added that VAR referees will be outfitted in uniforms identical to what their colleagues on the pitch will be wearing.

“It’s because they sweat like they do on the pitch,” he said last week. “It’s not like watching a game on the couch while drinking coffee. It’s very stressful so they can’t be dressed like a clerk.”

The opening match of the 2018 World Cup between host nation Russia and Saudi Arabia will kickoff on Thursday at 11:00 a.m ET.