In Sunday’s Broncos-Panthers game, Denver coach Sean Payton activated the replay process at a key moment, turning an incompletion into an interception.

As it turns out, the NFL also used replay to determine whether replay should be used to give the Broncos possession after Panthers tight end poppe the ball into the air in the end zone and Broncos safety Devon Key scooped it up before it touched the ground..

In a pool report, NFL V.P. of instant replay Mark Butterworth explained that replays were consulted to determine whether Payton had thrown the red challenge flag before the next snap.

“Replay can get involved to make sure that the head coach throws his challenge flag prior to the next snap,” Butterworth said. “We were actually able to use angles to show that the flag was out prior to the ball being snapped, and so we permitted the challenge.”

Although the rulebook doesn’t expressly state that replay may be used to determine whether replay can be used, the NFL relies on the first sentence of Rule 15, Section 9: “The Replay Official or designated members of the Officiating department may provide information regarding the correct application of the playing rules.”

And while Section 9 lists several specific examples as to when such consultation is permitted, the list is preceded by the phrase “including, but not limited to.” Which means that there may be other situations in which the Replay Official and/or the league office may assist the on-field officials.

One of those situations is whether a coach properly activated the replay process. Which allows replay to be used to determine whether replay should be used.