Unlike the NBA, the NFL and its teams frown on their best players skipping from town to town while in the prime of their careers. So it's worth understanding that the best players slated for this year's free agency already have been taken off the market through franchise tags and multi-year deals in advance of Tuesday's kickoff.
What's left are a few gems and a whole lot of question marks, red flags and older name players well past their prime. Judging any deal obviously depends on the compensation involved. But as a rule of thumb, here is one person's potential pitfalls to avoid and seven players to keep an eye on:
The rules in 2013
Over 28 in 2013? Move along, pal
The typical NFL player declines too rapidly and sometimes without warning. Signing older players can saddle a salary cap with too much "dead money" that's still on the books while the player is out of the league. Sorry Wes Welker, Greg Jennings, Sebastian Vollmer, Osi Umenyiora, Dwight Freeney, Charles Woodson, Ronde Barber and Brian Urlacher, to name a few.
Running backs? No thanks
Unless Adrian Peterson hits the market, skip running backs with high mileage. There are too many good, young, cheap models available to go spending money on a used one. Sorry Ahmad Bradshaw, Reggie Bush, Felix Jones, Steven Jackson and slippery little LaRod Stephens-Howling.
Injuries? No way, no how
A doctor can clear a guy, but if the guy's body is breaking down, it's breaking down. Jake Long is 28 and might be the best left tackle of his generation. But are you willing to pay more than $10 million a year to a man who might be heading down the same path that Tony Boselli traveled? Sorry Jake, Brent Grimes, Danny Amendola, Fred Davis and Kenny Phillips.
Former first-rounders? Beware
Watch out for household names. If a former first-round draft pick is on this list in his 20s, he's either a major injury risk, unreliable or he's been a flop for the past four years. Take on a resurrection project only when it's financially easy to bail when it fails. Sorry Sedrick Ellis, Glenn Dorsey and Dominique Rodgers-Cromartie.
Seven to select