(Associated Press)

Uruguay left back/midfielder Alvaro Pereira was knocked cold during after colliding with Raheem Sterling’s knee during Uruguay’s 2-1 victory over England on Thursday. After laying motionless on the field for a minute or two, Pereira awoke and wobbled to the bench. After some arguing with the team’s trainers, he returned to the game in the 63rd minute.

FIFPro, world soccer’s players’ union, is now asking FIFA to conduct an investigation of the incident, saying the world governing body’s concussion protocol “failed to protect” Pereira:

The World Footballers’ Association is seeking urgent talks and immediate assurances that FIFA can guarantee the safety of the players, which must be priority number one, for the remainder of this tournament and beyond.

In the absence of that, FIFPro is considering alternative solutions such as independent medical practitioners appointed by FIFPro for all future FIFA competitions.

FIFPro also calls for a review of the laws of the game so that a player with a suspected concussion can be temporarily replaced whilst being diagnosed.

“After the hit, I only recall that I was unconscious for an instant,” Pereira said, per the Associated Press. “It was like the lights went out a little bit.” He added that a team doctor and a FIFA physician examined him after the match, though a concussion has yet to be diagnosed.

FIFA’s concussion protocol takes “recognize & remove” as its mantra. Players suspected of suffering a concussion should be evaluated for visible clues or signs and symptoms, such as loss of consciousness, lying motionless on the ground or being unsteady on one’s feet, among a long list of other symptoms listed on FIFA’s Web site. “Any athlete with a suspected concussion should be IMMEDIATELY REMOVED FROM PLAY, and should not be returned to activity until they are assessed medically,” FIFA’s concussion guide says.