NEW YORK - Centralized spotters observing games on television were added to the NHL's concussion prevention protocols on Tuesday night.

The league already had in-arena spotters placed at all NHL games to start the pre-season, but they will now additionally have officials monitoring all games from the player safety room in New York City.

The centralized spotters will be authorized to require a player's removal from play for evaluation for concussion if the player exhibits certain visible signs under the protocol, following a direct or indirect blow to the head.

In-arena league spotters and on-ice officials will complement the central league spotters and will also monitor play for signs of possible concussion.

The league said the spotters have clinical experience working in elite level hockey, and have received training on the visible signs of concussion.