Despite presumably suffering a concussion at some point during last week's win over the Lions, Brandon Fusco didn't miss a snap. That, apparently, has led the NFLPA to launch an investigation into what happened.

According to a report from Pro Football Talk, the NFLPA is investigating whether the league's independent concussion spotter failed to recognize or take action "in response to the apparent struggles of Fusco to get to his feet after a block that involved helmet-to-helmet contact" in the third quarter.

In 2011, the NFL added independent certified athletic trainers (called ATC spotters) at every NFL game to watch for potential injuries. This year, the league has given the ATC spotters the ability to call down to the field for a medical timeout if he or she sees that a player may have been dinged.

So basically, the NFLPA reportedly wants to know why Fusco was allowed to keep playing with a concussion that wasn't disclosed until Wednesday.

As of Friday, Fusco had not been fully cleared through the NFL's concussion protocol, so he was not allowed to speak with reporters (or vice versa). Coach Mike Zimmer has not gone into specifics about Fusco's concussion.

Fusco was listed as questionable for tomorrow's game against the Chargers.