Everybody can use a refresher on OT rules. (Andy King / Associated Press)

Update, 8:15 p.m.: The rule wasn’t a factor in the Denver Broncos-Pittsburgh Steelers game as Tim Tebow threw an 80-yard touchdown on the first play from scrimmage in overtime.

It isn’t just Donovan McNabb who could use a refresher course about overtime rules, particularly when the NFL postseason begins and things change.

A new rule went into effect with last year’s playoffs — but not a single game was tied at the end of regulation so it’s been on ice since the Super Bowl ended. (During the regular season, the first team to score in OT is the winner. As Donovan knows.)

From the NFL, here’s what happens in OT in the playoffs:

“The modified system of determining the winner shall prevail when the score is tied at the end of regulation for postseason NFL games. The system guarantees each team a possession or the opportunity to possess, unless the team that receives the opening kickoff scores a touchdown on its initial possession.

“At the end of regulation time, the Referee will immediately toss a coin at the center of the field in accordance with rules pertaining to the usual pregame toss. The captain of the visiting team will call the toss prior to the coin being flipped.

“Following a three-minute intermission after the end of the regulation game, play will be continued in 15-minute periods until a winner is declared. Each team must possess or have the opportunity to possess the ball unless the team that has the ball first scores a touchdown on its initial possession. Play continues in sudden death until a winner is determined, and the game automatically ends upon any score (by safety, field goal, or touchdown) or when a score is awarded by the Referee for a palpably unfair act. Each team has three timeouts per half and all general timing provisions apply as during a regular-season game. The try is not attempted if a touchdown is scored. Disqualified players are not allowed to return.”

As for instant replay, “No challenges are allowed. All reviews are initiated by the replay official.” 

Now, just what does the NFL mean by “possession” and “opportunity to possess.” Seems clear, but let’s set forth the rule...just because.

Possession: Actual possession of the ball with complete control. The defense gains possession when it catches, intercepts, or recovers a loose ball.

Opportunity to possess: The opportunity to possess occurs only during kicking plays. A kickoff is an opportunity to possess for the receiving team. If the kicking team legally recovers the kick, the receiving team is considered to have had its opportunity. A punt or a field goal that crosses the line of scrimmage and is muffed by the receiving team is considered to be an opportunity to possess for the receivers. Normal touching rules by the kicking team apply.”

Got it?