Sources: NFL special teams coordinators are meeting in the next hour to clarify a kickoff rule that some teams are believed to have misunderstood — or found a loophole in — through the first two weeks of the season. The NFL allows a 12th player on the field to hold the ball on kickoffs, but teams including the Eagles last week and Falcons in Week 1 used that extra player to hold the ball without a tee, giving the kicker a different launch angle to create a more difficult “dirty” kick and potential field-position advantage. The clarification coming today: If a 12th player is used to hold the ball, the ball must still be placed on a tee. My understanding is that the clarification may not be fully enforced for this week’s games.