The NFL is enjoying another successful season on the field, where several teams harbor Super Bowl aspirations with two weeks left in the regular...

The NFL is enjoying another successful season on the field, where several teams harbor Super Bowl aspirations with two weeks left in the regular season, and in the Nielsen television ratings, where gridiron games remain, by far, the most popular shows in prime time. Through 14 weeks, 26 NFL games had been watched by more than 20 million viewers — only nine other programs garnered such an audience — while NBC’s Sunday Night Football has been the top-ranked program in each of its 15 weeks.

But not all the NFL news is good. Attendance is likely to decrease for the third straight season and 21 games have not sold out and have, as a result, been blacked out in the home team’s market. There were 22 blackouts last year, more than 2007 and 2008 combined and the highest figure for the NFL in at least five years.

Two games were blacked out Sunday, December 19: The battle for Ohio between the also-ran Cincinnati Bengals and Cleveland Browns in Cincinnati and the AFC West matchup between the Oakland Raiders and Denver Broncos in Oakland.

Those blackouts were particularly discouraging signs for the NFL. While the Browns and Bengals are playing out the string as usual, this was the first non-strike season since 1979 that a Browns-Bengals game in Cincinnati did not sell out. The Raiders-Broncos rivalry is to the west coast what Browns-Bengals is to Ohio and the Raiders, which snapped an NFL-record streak of seven straight 10-loss seasons this year, remained in contention in the AFC West with their 39-23 win.

The NFL will almost surely break last year’s sellout mark this Sunday, December 26, when both the Bengals (three blackouts) and Tampa Bay Buccaneers (blackouts for all seven home games) host the San Diego Chargers and Seattle Seahawks, respectively. The Buccaneers, which are 8-6 a year after going 3-13, have been one of the league’s most surprising teams, but any hope of a sellout likely disappeared when the Buccaneers were upset by the Detroit Lions last weekend to all but fall out of playoff contention.

The Raiders may avoid their seventh blackout in eight games at Oakland Coliseum this Sunday (the only exception: their 23-20 overtime win over the Kansas City Chiefs Sunday, November 7), when they host the Indianapolis Colts, who are tied for first place in the AFC South and feature one of the league’s biggest names in superstar quarterback Peyton Manning.

A competitive final day of the regular season Sunday, January 2 could spare the NFL additional blackouts. As of today, December 21, the only game on the week 17 schedule that pits two teams already out of playoff contention is the Minnesota Vikings-Detroit Lions game in Detroit.

In addition to the 21 games that have been blacked out, several NFL teams — from contenders such as the Chargers and Jacksonville Jaguars to sub-.500 teams such as the Detroit Lions — have needed 24-hour extensions from the NFL in order to avoid blackouts. Games must be sold out within 72 hours of kickoff in order to be aired locally.