Rui Patricio was left flat on his back before departing on a stretcher in a shocking incident in the final minutes of the Premier League clash between Wolves and Liverpool.
The 33-year-old goalkeeper appeared to collide with one of his teammates, Wolves skipper Conor Coady, when he rushed out of his goal in a brave attempt to thwart a Liverpool attack.
Medics rushed to attend to the prone Portuguese, spending seven minutes on the pitch while players and staff on both sides looked deeply shocked.
The accident was a horrific reminder of the head injury that ruled Wolves striker Raul Jimenez out for the rest of the season in November.
Speaking on BBC Radio 5 Live, former England goalkeeper Rob Green said: 'Even if it was the impact on the head, the whiplash through the neck and the damage that can be done can be quite great.
'They have to make sure his welfare is taken care of before they move him. They already had one serious head injury this season. If there's a club that's depserate to get this right after what happened to Raul Jimenez, it's Wolves.
'[Concussion substitutions is] such an obvious answer that you wonder why it took so long [to implement].
'It allows teams to make substitutions freely and be more positive in their subs. The last thing you want is for these closing minutes to be marred because a team has been reduced to 10 men through no fault of their own.