Posted by Doug on May 16, 2007
Last year I posted a description of Bill James' "Favorite Toy," which is a quick way to estimate players' chances of reaching certain milestones. It's not based on rigorous mathematical principles, as far as I'm aware, but it usually gives answers that feel about right.
Before last season, the toy (with a slight tweak) estimated the following probabilities of breaking Emmitt Smith's career rushing yardage mark.
Runner Pct Chance Clinton Portis 26.5 Edgerrin James 21.3 LaDainian Tomlinson 17.3 Shaun Alexander 11.3
With one more year in the books, here's where we stand:
Runner Pct Chance LaDainian Tomlinson 27.5 Edgerrin James 12.2 Steven Jackson 8.4
Portis drops off the chart because the system estimates how good a player is largely by considering his previous season's numbers, and Portis's obviously weren't very good. While a fantastic 2007 can get him back in the race --- a 1750-yard season would put him around 15% --- a mere 1200-yard season won't do much for him. Portis was ahead of Smith in through-four-years rushing yards, but trails him by about 700 yards on the through-five-years list. And Emmitt tacked on another 1773 in his sixth year. You just can't afford to lose a season in your prime.
Meanwhile, LaDainian Tomlinson is now a couple hundred yards ahead of Smith on the through-six-years rushing yardage list. But he entered the league a year older than Emmitt did.
Here are the estimated chances of Jerry Rice's records being broken by various people:
Receiver Pct Chance Torry Holt 18.9 Andre Johnson 12.3 Chad Johnson 10.9 Marvin Harrison 10.9 Larry Fitzgerald 10.7 Anquan Boldin 9.0 Tony Gonzalez 7.6 Laveranues Coles 3.7 Reggie Wayne 1.9 Antonio Gates 1.5
Receiver Pct Chance Torry Holt 12.2 Chad Johnson 12.0 Larry Fitzgerald 5.4 Anquan Boldin 3.9
Receiver Pct Chance Marvin Harrison 10.0 Terrell Owens 4.8 Antonio Gates 1.5