Arsenal forward Beth Mead was forced off late in the tie following a clash of heads, after the Gunners had already used up their allocation of three windows for substitutions during the match.
It initially seemed winger Lina Hurtig would be allowed to come on as a concussion replacement, only for Arsenal boss Jonas Eidevall to be informed by the referee that the protocol is not in place in the competition, though the Swede claimed afterwards that the officials themselves had not been sure of the rules.
“The problem that I have is that I asked the fourth official if we can do a concussion sub and she says ‘yes’,” Eidevall said.
“Then when we are preparing Lina and when we are about to do it she says ‘no.’
“We had a break for two or three minutes while Beth was treated, we would have been talking about how to play with ten. That misinformation from the referee - I don’t understand it.”
Permanent concussion substitutes are currently an option in a number of domestic leagues, including the Premier League and WSL, as part of a trial initiated by the game’s lawmakers IFAB, which was originally due to run only until this summer but has since been extended until August 31, 2023.
The measure, which allows teams to replace one player per match without it impacting their usual allocation of substitutions, is designed to encourage teams to prioritise player welfare without fear of putting themselves at a sporting disadvantage.
Concussion substitutes will be allowed at the World Cup in Qatar later this year, with Fifa confirming that changes following head injuries will be permitted regardless of the number of substitutes or substitute intervals already used.
However, major European competitions such as the Champions League, Europa League and Uefa Nations League, have no such provision, though European football’s governing body did trial the scheme at last year’s U21 Euros.
Some campaigners, including brain injury charity Headway, insist even the trial measures do not go far enough and want temporary concussion substitutes introduced, similar to those in rugby, in order to allow more time for proper assessment of players’ conditions.