If you didn't see it, there was a very scary moment late in the Espanyol match when Sergio Asenjo leapt for a ball and came down over the top of Chechu Dorado, landing on his (Asenjo's) neck and head. He did not appear to be knocked out, and remained in the match after treatment.
He made a save or two afterward, though why he was leaving his goal to scream at one of the Espanyol players when play was continuing in the box, I don't know!
After the match he went to the hospital to be checked out, and spent the night there under observation. He seems to be OK, but here is yet another case where concussion protocols, if they exist, were ignored.
Yes, Villarreal had used all their subs, so would have had to put an outfield player in goal and play a man down, which would have been bad for us. However, there has to be some ability to overrule a player's natural desire to stay in there; did the club doctors feel he was OK, or did Asenjo overrule their desire to take him off? (It certainly seemed to begin with he would be substituted).
Not sure how seriously he was concussed, but Javi Mata, commenting on the radio, felt Asenjo was groggy immediately after the incident. That right there should have been enough to require him to leave the match, shouldn't it? More questions than answers, but that's how it feels with the entire concussion issue in soccer right now.