DENVER—At Tuesday night's Colorado Avalanche game against the Nashville Predators, two people, paid by the NHL, intently watched players from each team for any sign that they might have just suffered a concussion. At the NHL's midtown Manhattan office, another four league-employed people monitored that and other games from the night on televisions and other private camera angles, looking for the same warning signs of concussion.
Down on the ice, trainers from the Avs and Predators had walkie-talkies on their hips, in case any of the four concussion "spotters" needed to radio their concerns over any particular player.