NFL Week 5 Probabilities, and Jets' Folly With Sanchez The most ill-advised off-season transaction in 2012 belongs to the Jets. I'm not talking about Tim Tebow. I'm talking about the Mark Sanchez extension. Ostensibly designed to open cap space, the extension cemented Sanchez as the principal quarterback for the Jets through this season and the next one, with guarantees of around $20.5 million. This was an enormous mistake. Quarterbacks typically improve significantly from their rookie season to their second season, but they soon plateau at a relatively steady career-long level of performance. Sanchez's net adjusted yards per pass attempt went from 3.5 in his rookie year to 4.7 in 2010, 4.2 in 2011 and 4.5 so far this year. Say what you want about the team around him. He has had talented linemen, backs and receivers. Many league quarterbacks would be happy to have Dustin Keller, Santonio Holmes (now out for the season) and even Plaxico Burress to throw to over parts of the last four seasons. The league pays its quarterbacks according to overall production. Over the past decade, quarterbacks get about $1 million in salary per 8.4 Expected Points Added (EPA) they produce. EPA is a measure of point expectancy generation that accounts for down, distance and field position. For example, Drew Brees and Peyton Manning were offered about $20 million per year, and they have recently produced around 150 EPA per season. Sanchez should be expected to produce over 80 EPA per season based on his $10 million salary, but he averages only 4 EPA per season in his career. His very best year was in 2010, when he totalled 18 EPA. For context, the 16th-ranked quarterback totalled 50 EPA that year. If we want to look at Win Probability Added (WPA), which accounts for situational football affected by time and score, Sanchez fares no better. Quarterbacks average $1 million for every 0.20 WPA they accumulate. Sanchez has produced a hair under zero WPA for his career, which is essentially replacement-level performance. Statistically, he should be paid the $300,000 veteran minimum rather than the multi-million dollar salary he was given. Teams like the Jets hold on tight to poorly performing quarterbacks for a number of reasons. They have spent high draft picks and attached their reputations to the players' success. General managers and other team executives are wedded to sunk costs they paid but will never recover. I think they are also affected by the endowment effect, a phenomenon in which people irrationally overvalue something simply because they own it. Although injuries will be blamed for the Jets' under-performance this season, their fate was probably already sealed. The offensive passing game is primarily why the Texans and their fourth-best passing efficiency will be heavily favored when they visit the Jets, with their 25th-ranked passing efficiency, on Monday night. Here are the game probabilities for Week 5: (For an explanation of how Brian's system works, go here.) Brian Burke, a former Navy pilot who has taken up the less dangerous hobby of N.F.L. analysis, operates Advanced NFL Stats, a blog about football, statistics and game theory.