(from April 2013) at NFL.com gives a little more detail.
With NFL Network's "Thursday Night Football" schedule being extended in 2012, every NFL team is guaranteed at least one prime-time appearance. The maximum a team can be scheduled is five times, although that number can go up one game depending on flex scheduling late in the season. How many times a team is scheduled for prime time is a nice, clean look at the NFL.
These are the teams the NFL wants to sell. They are the teams that get television ratings and/or play games that matter. Here's a rundown of how many prime-time games each team will play in 2013:
- 5: Denver Broncos, New England Patriots, Atlanta Falcons, New York Giants, San Francisco 49ers and Washington Redskins
- 4: Baltimore Ravens, Houston Texans, Indianapolis Colts, Pittsburgh Steelers, Chicago Bears, Dallas Cowboys, Green Bay Packers, New Orleans Saints and Seattle Seahawks
- 3: Cincinnati Bengals, Miami Dolphins, San Diego Chargers and Minnesota Vikings
- 2: New York Jets, Carolina Panthers, Philadelphia Eagles, St. Louis Rams and Tampa Bay Buccaneers
- 1: Cleveland Browns, Buffalo Bills, Jacksonville Jaguars, Kansas City Chiefs, Oakland Raiders, Tennessee Titans, Arizona Cardinals and Detroit Lions
It's still not clear where the "maximum of 3 teams" that can be flex-scheduled to six comes from.
The article doesn't say: is it implicit that a team cannot be flexed out
of its only prime-time appearance? I haven't checked the schedule - are all of those "one-timers'" games in the early part of the season, before flex scheduling kicks in?