The darkest December.

The past two weeks have been just that for the NFL. This is supposed to be the happiest, most exciting month for pro football. As Christmas lights turn on and holiday spirits soar, the season reaches its crescendo with playoff contenders jockeying for position. For fans, it’s a gift that slowly unwraps and reveals itself.

This month, though, the games and playoff races have shrunk in significance. Remember early in the season when the calamity over replacement game officials seemed so important?

On Dec. 1, Chiefs linebacker Jovan Belcher murders his girlfriend and then kills himself, orphaning their 3-month-old daughter. He takes his own life at the team’s stadium, as his horrified coach looks on. The girlfriend killed, Kasandra Perkins, was the cousin of the wife of Belcher’s Kansas City teammate, Jamaal Charles.

Unimaginable. Unspeakable.

Almost exactly one week later, Cowboys linebacker Josh Brent is arrested for intoxication manslaughter. It was after a night in which a dozen or so Cowboys partied at a local club, ordering bottles of expensive champagne, and then one of them, Brent — according to the arrest report — caused the one-car accident that killed teammate Jerry Brown.

Unimaginable. Unspeakable.

How do you respond? Chiefs players want to honor Belcher, but being a missed teammate does not erase the fact he departed as a murderer, too. Cowboys coach Jason Garrett said, “We will support Josh 100 percent.” And yet that is the player who police say caused a teammate’s death.

These two tragedies were still being mourned when this week’s news broke about the NFL punishment of Saints players being overturned in the so-called Bountygate case. It is a black eye for commissioner Roger Goodell, a blow to his leadership and reputation. But don’t make more of it than that.

Not now.

Not when Kansas City and Dallas and football fans in general must face that the unimaginable can occur, the unspeakable, when their Sunday heroes reveal weaknesses greater than all of their strength.

Scatter-shooting the league:

• Updated playoff likelihood via makenflplayoffs.com: AFC — Broncos, Texans and Patriots have clinched. Ravens 99.9 percent likely and Colts 99.4 (both can clinch this week). Steelers are at 49.1. Bubble: Bengals, 38.9. NFC — Falcons have clinched. 49ers 98.7 percent likely and Packers 90.1 (both can clinch this week). Giants are at 73.3, Seahawks 72.8 and Bears 55.3. Bubble: Redskins 39.9.

• Indianapolis, 9-4 after last year’s 2-14, aims to be only the fourth team to win 10-plus games a season after winning two or fewer. The others: Raiders, 1-13 to 10-4 in 1962-63, Baltimore Colts, 2-12 to 10-4 in 1974-75; and Dolphins, 1-15 to 11-5 in 2007-08.

• Tackle Jake Long has fallen from first to fourth in AFC Pro Bowl fan voting at his position, leaving punter Brandon Fields as Miami’s only leader with four days of voting left. DE Cam Wake (third) and DT Randy Starks (fifth) also are running top five.

• Three rookie QBs (Russell Wilson, Andrew Luck, Nick Foles) have thrown a winning TD pass on the game’s final play. That had previously only happened twice since 1970: Tim Couch in 1999 and Matthew Stafford in 2009.

• The Bears’ Brandon Marshall tied Marvin Harrison, Jerry Rice and Wes Welker with a fourth 100-catch season. Welker (with 95) aims for a record fifth this week.

• NFL is considering expanding its playoffs from 12 teams to 14 or 16. The last increase (10 to 12) was in 1990.

• Niners’ Aldon Smith has 19 ½ sacks. He needs 3 ½ in final three games to break Michael Strahan’s 2001 record of 22 ½.