What happened: Smith slipped on wet grass at Wembley Stadium on Sunday and fell on his back, then fell again trying to stand between plays. Trainers from both teams attended to him before he left the field on a cart. The injury was identified as a torn quadricep, per FootballZebras.com.

Why it matters: The crew finished the game with six officials, splitting umpire duties. Smith was working his first NFL season after college and spring-league assignments. The league will need a replacement umpire for the remainder of the season.

What to watch: Watch who the league adds to fill the umpire vacancy.