The Professional Footballers’ Association has reiterated its call for the introduction of temporary concussion substitutes amid some confusion when Sheffield United defender George Baldock suffered a head injury at Leeds.

Baldock came off worst following his robust first-half challenge on Leeds attacker Tyler Roberts, appearing to bang his head on the Elland Road turf before being treated on the pitch and touchline as concussion checks were made.

He was sent back into the fray but was replaced by Ethan Ampadu five minutes later on the stroke of half-time, with interim Blades manager Paul Heckingbottom explaining afterwards that Baldock was experiencing “blurred vision”.

Alan Shearer was critical of the delay in bringing off Baldock and the PFA says the incident has shone a light on the necessity of temporary substitutes to supplement permanent replacements in the event of head injuries.

The PFA backed temporary concussion substitutes earlier this year and, in light of Saturday’s episode, once again urged the International Football Association Board to bring in the measure for the start of the 2021-22 campaign.

In a series of tweets, the PFA said: “Head injuries in yesterday’s game between Leeds United and Sheffield United again highlighted the case for temporary substitutions.

“Temporary replacements would give additional assessment time and allow medical teams to conduct assessments in an appropriate environment.

“Temporary substitutes would mean that a match can restart with neither side numerically disadvantaged, reducing pressure on players and medical teams to make quick decisions.

“In December 2020, IFAB announced a trial to introduce permanent concussion substitutes. Despite a relatively low take-up of the trial globally, the Premier League, The FA and WSL are all participating.

“We welcome the fact that English football is taking the lead on this issue. However, we call on IFAB to add temporary concussion substitutions to the trial for the start of next season.”

Leading brain injury charity Headway described the existing rules on concussion substitutes as “deeply flawed” following a similar instance of uncertainty involving West Ham’s Issa Diop against Manchester United on February 9.

Former Newcastle and England captain Shearer was critical at the treatment of Baldock, saying in his pundit role with Amazon Prime: “I look at it and I think, when is football going to learn? If in doubt, sit them out.

“He’s been assessed, he’s been allowed back on to the football pitch for five minutes and then clearly he’s not right and then they take him off again. What is football waiting for, what is it doing allowing this?”

Heckingbottom insisted the club had followed concussion procedures, as he said: “George was a concussion substitution. He went through the test and appeared fine but reported some blurred vision so we brought him off.”