From the Chronicle.

Schar was knocked out for four minutes after a clash of heads and looked to be unconscious, sparking fears that he was in serious trouble. There were fears he may have swallowed his tongue and players from both sides rushed to his aid.

But after lengthy treatment the centre-back recovered to set up goals for Steven Zuber and Denis Zakaria in the 2-0 win.

That last part baffles me although im glad he recovered and got 2 assists he shouldn't have even been on the pitch should he? i thought an injury like that (loss of consciousness) means u get subbed off.