Mike Pereira knew instantly last Sunday that the NFL had a big problem.

The league's vice president of officiating was in the command center at his office in New York, where he spends every Sunday during the season. He was surrounded by enough television screens for him and his colleagues in the officiating department to watch 10 games at once, and he saw referee Ed Hochuli botch the call in Denver that almost certainly cost the San Diego Chargers a victory and ignited a controversy that raged all week.

Like nearly everyone else watching the game, Pereira knew that Hochuli had blown the call by signaling an incomplete pass when the ball slipped from the hand of Broncos quarterback Jay Cutler. But Pereira knew more than other observers. He knew that the NFL rulebook prohibited Hochuli from overturning the erroneous call via an instant replay review. He knew plenty of people were about to be very, very agitated.

"It was one of those where you knew immediately," Pereira said in a telephone interview late in his hectic week. "I saw the play and I knew right away it was a mistake, just like Ed knew when he looked under the hood it was a mistake. The thing I knew right away because of the rule was that San Diego wasn't going to get the ball. Any time something like that happens at that point in a game, you know it's gonna be a firestorm. At that point, it becomes a matter of alerting everyone -- the commissioner, the PR staff -- what's coming."

The Hochuli call put in motion a week of apologizing and agonizing for the veteran referee and for everyone else in the officiating department. NFL representatives said Hochuli's misjudgment would affect his grade in the elaborate evaluation system the league uses for officials to determine which of them earn postseason assignments and which are retained the following season. But few outside the league know just how exacting that grading system is.

It all begins in the Sunday command center with Pereira and his cohorts stationed by screens monitoring every game. There are 10 TV feeds into the room, plus one huge screen on which Pereira can put the feed of his choosing. Every penalty called in every game is charted, along with every injury and every play that might result in a player being disciplined by the league. Pereira bounces from screen to screen when summoned by a co-worker.

"Someone might shout out to me, 'Hey, Mike, I have a roughing-the-passer in Cincinnati,' and I'll go over and look," he said. "I'll look at the replay and see if it was right. I really most likely would be able to tell you within 20 seconds if the call is correct or not.

"Really, I pretty much have a pulse on what has happened pretty much as it's happening. I want to be prepared for the coaches' calls I get Monday. I want to have a head's up. Ninety percent of the time when a coach calls me, I know what he's calling about."

Around 1 a.m. each Monday, a couple of hours after the Sunday night game is done, Pereira does a video recording for NFL Commissioner Roger Goodell with any officiating controversies from Sunday's games. He puts it on Goodell's desk around 2 a.m. so Goodell can view it when he gets to the office, just in case any angry team owners directly call the commissioner.

Each Monday, Pereira and his seven officiating supervisors gather to evaluate all of that weekend's games. They divide up the games, meaning each of them gets an average of two per week, and go through them play by play. The average game has about 153 plays. The person doing the evaluating looks at the TV shot and replays of each play and also at the coaches' tape of the play, with one thing in mind: Was it officiated correctly? If the answer to that is yes, the officiating crew gets marked for having the play correct. If not, the questions are: Who made the mistake? And why?

Each officiating crew receives a first report on the game it worked that weekend. Pereira calls this report a "project." There are notes and thoughts on individual plays. He read a few notes from Monday night's Eagles-Cowboys game as examples. On one first-quarter play, an official called holding but the report said: "When you look at it on the coaching tape, it just doesn't seem strong enough."

Each official is given a chance to respond on any call alleged to have been wrong. Then each Wednesday, Pereira and his supervisors meet and go over each of those calls. The group is told what the report says and what the official's response was. Sometimes the official agrees that a mistake was made; sometimes not. The play is shown and a vote is taken on whether an error was made. Majority rules. In the case of a 4-4 tie, the official gets the benefit of the doubt and no mistake is charged.