■Turnovers: Players will have to be mindful of what they do if they pick up a fumble or intercept a pass on the opening possession. If a player fumbles the ball back to the other team and it kicks a field goal, the game is over because the defense had a possession. Also, if you’re trailing by a field goal, the pressure will ratchet up to hold onto the ball because you won’t get an opportunity for a stop on defense.

■Onside kick: If a team opens with a field goal, it has to give at least some thought to an onside kick because if it recovers, the game is over because it counts as a possession for the other team.

■Fourth-down attempts. Obviously the team trailing by a field goal has to go for it on fourth down in their own end. But if you take the opening kickoff, will you be more aggressive near midfield to put points on the board? If it’s fourth and short, do you take the field goal or go for it in the hopes of getting a touchdown to win the game?

“A ton of new options come into play now. You’re going to try to have a plan but, really, you’re going to be flying by the seat of your pants. No, I’m not a fan.’’

“We haven’t talked about it yet, but I know we will,’’ said an assistant coach of an NFC playoff team. “It’s something that’s completely new. There’s nothing even remotely close to refer back to.

It doesn’t seem to be a huge difference, but it is to coaches who have none of their beloved scripts and charts to work from.

A defensive score of any kind ends the game because it would count as a possession for both teams.

If the receiving team kicks a field goal, the other team gets a possession. A field goal would put the game into sudden death. A touchdown ends the game.

A quick refresher: Instead of sudden-death overtime used in the regular season, each team will get a possession in overtime unless the receiving team takes the kickoff and scores a touchdown. Then the game is over.

When the NFL postseason kicks off Saturday, a completely unfamiliar scenario could unfold as the new postseason overtime rules are enacted for the first time since the owners — not the coaches — approved them by a 28-4 vote last March.

What football coaches hate most is curveballs. And they will be figuring out how to deal with a big one — in the most important games of their careers — this week.

■Take the ball or kick off?: Under the regular-season rule, the team winning the toss took the ball. You score, you win. Jets coach Rex Ryan — always confident — said at the owners meeting that he would kick off because a defensive stand and then a field goal would win the game. He changed his tune yesterday (maybe because his defense isn’t that good anymore).

“We will actually take the ball if we win the coin toss in overtime,’’ Ryan said.

Saints coach Sean Payton, who has been known to take a risk or two, agreed.

“It would be real difficult to decide to kick off and have them return the opening kickoff for a touchdown and the game end,’’ he said.

Mostly, coaches said, a lot of the decisions are going to have to be based on feel since there’s no precedent.

“I think you’ll pay attention to how the game is progressing,’’ Payton said. “How the first four quarters have gone would predicate your decision on how you would handle it.’’

With the new overtime rule in mind, here’s a primer on what to watch for in the first four games.

Saints (11-5) at Seahawks (7-9): New Orleans, the defending champion, is a 10.5-point favorite over the first team to ever make the playoffs with a losing record. An upset would not be shocking. All three teams that made the playoffs with 8-8 records since the current format was instituted in 2002 won their games (Chargers in 2008, Vikings in ’04, Rams in ’04). Qwest Field is notoriously one of the toughest places to play, and with a short week and a trip to the West Coast, the Saints will fly out Thursday night. The Seahawks, who haven’t decided whether Matt Hasselbeck or Charlie Whitehurst will start at quarterback, were no match for the Saints Nov. 21 at the Superdome as Drew Brees passed for 382 yards and two touchdowns in a 34-19 victory. The Saints had three key players — safety Malcolm Jenkins (right knee), tailback Chris Ivory (left foot), and tight end Jimmy Graham (left ankle) — leave the season finale with injuries, and Ivory has gone on IR.

Jets (11-5) at Colts (10-6): Same matchup and locale as last season’s AFC Championship game, which the Colts won, 30-17, after the Jets got out to a 17-6 lead. The Jets think they’re better prepared to stop Peyton Manning this time around after acquiring cornerbacks Antonio Cromartie and Kyle Wilson, safety Brodney Pool, and linebacker Jason Taylor in the offseason. Manning has won five of six matchups against Ryan, including two in the playoffs. “I don’t know when I’m going to beat him, but I want it to be Saturday,’’ Ryan said. “Is it personal? Yes.’’ The Colts have been vastly improved running the ball (133.5 yards per game) and stopping the run (79.8) in the past four games.

Ravens (12-4) at Chiefs (10-6): Arrowhead Stadium, where Kansas City was 7-1 this season, hosts its first playoff game since the ’03 season. While Chiefs coach Todd Haley was on the Cardinals staff that went to the Super Bowl, this is his first playoff game as a head coach. It also will be new for quarterback Matt Cassel and many of the Chiefs, who beat one playoff team (Seahawks) this season. The combined record of their 13 opponents was 85-123. The Ravens are making their third straight playoff appearance under coach John Harbaugh and won the previous two wild-card games on the road, including last year’s 33-14 victory at New England. “I think it’s a benefit — the fact that we’ve been through it two years in a row’’ Harbaugh said.

Packers (10-6) at Eagles (10-6): Rematch of the Packers’ season-opening 27-20 victory at Lincoln Financial Field. But, oh, how these teams have changed (a combined 14 different starters since the first time around). The Packers actually helped the rise of Eagles quarterback Michael Vick because they knocked Kevin Kolb out of the game with a concussion. The Packers are missing key cogs in tight end Jermichael Finley, running back Ryan Grant, and linebacker Nick Barnett. But they’ve played well the past three games (two wins and a close loss to the Patriots with backup Matt Flynn at quarterback). “I think it’s, I don’t want to say wide open, but we feel very confident with our chances,’’ said Packers coach Mike McCarthy.

Greg A. Bedard can be reached at gbedard@globe.com. Follow him on Twitter @greg_a_bedard.

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