NFL games have begun for 2015.

Don’t bother checking out your Sunday Ticket, though. This is not football the teams are playing, it’s tag.

Monday was the deadline for franchises to decide whether to hold onto key players who are pending free agents by giving them the franchise or transition tag. The alternative: letting them hit the open market on March 10.

The New England Patriots used their franchise tag on three-time Pro Bowl kicker Stephen Gostkowski. If they can’t reach a deal with him by July 15, they will have to pay him $4.126 million in 2015.

A lot more goes into tagging than simply wanting to hold on to a standout or a budding star. There’s nearly as much game-planning for it as there is for an opponent during the season.

Teams ask themselves:

What position does he play and how much is the tag for that position?

 Should we use the exclusive franchise tag, when no other team can approach the player? Or go with the non-exclusive, allowing other teams to pursue the player, but with the original team able to match any offer, or decline and gain two first-round draft picks?

 Should we go with the lower transition tag, in which other teams can set the market for a player and if the contract is not matched, there is no compensation when the player walks?

 What is our salary cap situation? Does it make sense to commit so much money to one player? Is he that much of a difference maker?

This year, the Lions decided not to tag Ndamukong Suh, an All-Pro defensive tackle and, when on his game, a wrecking ball on the field. Among the reasons could be his penchant for unacceptable on-field behavior.

More likely, Detroit looked at the salary cap implications of tagging Suh for nearly a $27 million cap hit because of his previous contract restructuring. The Lions felt adding to the huge price tags on receiver Calvin Johnson and quarterback Matthew Stafford would preclude the team from improvements in several other areas.

No team wants to commit more than 30 percent of its cap spending to three players – unless those players have won championships for the franchise. Most teams prefer to stay under 25 percent for its top three players. Stafford has a salary cap hit of $17.7 million in 2015, and Johnson is at $20.5 million.

Detroit still might sign Suh to a long-term deal, and it could avoid the hefty one-year cap hit with some creativity over a span of a few seasons. That room for creativity doesn’t exist with franchise-tagged players.

Kansas City bit hard and put the non-exclusive tag on linebacker Justin Houston. Except Houston might want to be considered a defensive end: the tag at that position is nearly $1.7 million higher.

While the Chiefs negotiate with Houston’s agents, they also must find ways to trim salaries. That shouldn’t be too difficult; much harder will be dealing with a potentially long holdout by Houston if the sides can’t agree on which position the league’s leading sackmaster plays.

The Giants had an easier decision in franchising defensive end Jason Pierre-Paul. When healthy and motivated, he’s a force, as his 121/2 sacks and 21 quarterback hits for a weak defense showed in 2014. He also had 161/2 sacks in 2011, and is only 26.

With Steve Spagnuolo returning as defensive coordinator, New York will build again around the pass rush. Pierre-Paul is the foundation.

Denver also had little choice with tagging receiver Demaryius Thomas at $12.823 million. With Peyton Manning likely to return this season, the Broncos had no option but to keep his top target – particularly with tight end Julius Thomas and wideout Wes Welker unsigned.

Dallas, as expected, tagged its All-Pro receiver, Dez Bryant. The Cowboys are in a tight spot because they have little maneuverability for 2015 if they can’t get a long-term agreement with Bryant. Failing to do so could mean losing AP Offensive Player of the Year DeMarco Murray, the league’s top running back.