By Madison Williams An investigation regarding Dolphins quarterback Tua Tagovailoa clearing concussion protocol last Sunday before re-entering the game is ongoing. The NFL Players Association reportedly fired the unaffiliated neurotrauma consultant who was involved in Dolphins quarterback Tua Tagovailoa’s evaluation last Sunday after it was found the doctor made “several mistakes,” a source told ESPN’s Marcel Louis-Jacques. The NFLPA launched an investigation after Tagovailoa was cleared to play last Sunday vs. the Bills after he stumbled off the field following a major hit. He cleared concuss…