The NFL sent a memo to all 32 teams on Wednesday underscoring that team's game-day staff must know their roles and abstain from involving themselves in any game altercations or making physical contact with another team's player. 

The memo came in the wake of Week 13's sideline altercation between San Francisco 49ers linebacker Dre Greenlaw and Philadelphia Eagles head of security Dom DiSandro.

"Please ensure that all members of your game-day staff understand that their role does not extend to being involved with game day altercations and that they must refrain from such involvement," the memo read.

Sunday's matter remains under investigation by the NFL.