Greenlaw approached referee Brad Allen following his team's win on Sunday against the New York Giants after it looked like Allen shoved Denver Broncos player Justin Strnad.
Reports have said that Greenlaw threatened Allen as he was leaving the field.
Sunday was Greenlaw's first game of the season after coming off the injured reserve list with a quadriceps tear. He recorded six tackles and a quarterback hit on his lone pressure.
Greenlaw also proved to be useful in the pass game, allowing no catches on two targets.
Now, the 28-year-old linebacker will miss the Broncos' game against the Dallas Cowboys on Sunday, October 26th.
Greenlaw signed a three-year, $31.5 million contract with the Broncos in the offseason after spending the first six years of his career as a member of the San Francisco 49ers.