Tillman: One of the League's Worst?

Football Outsiders has developed a new analytical tool to rank the 2010 cornerbacks. Charles Tillman didn't do so hot. Going forward, can Chicago rely on him to be the same player he was in the past?

Statistics in football can be deceiving. Unlike baseball, where the numbers tell most of the story, football is a true team sport, where each player's actions have an immediate affect on the statistics of the players around him. There are 22 players on the field at any given moment, the most of the four major American sports. There has to be cohesion among all 11 teammates in order for plays to execute properly. If one cog fails, the whole machine shuts down.

On the surface, a running back's poor yards-per-carry average indicates a player not performing at a high NFL level. But look closer and you may see a player who has a weak line in front of him, a group that failed to create holes for him to run through. His statistics may look bad but they don't tell the whole story.

Then there are positions that don't have hardly any substantial statistics by which to evaluate players. Without sitting and watching tape on each individual player, how can anyone objectively rate offensive linemen through statistics alone? It's virtually impossible.

The same goes for most defensive positions. Julius Peppers' numbers alone last year don't indicate a sure-fire Pro Bowl player. But anyone who watched him knew his value to the team went far beyond his number of sacks.

CB Charles Tillman
Jonathan Daniel/Getty

The defensive secondary is another hard position to evaluate. Sure, interceptions look great and often earn players huge contracts, but they don't really show the value of a player. During any given season, a defensive back could get four interceptions due solely to the fact the receivers he was covering fell down, and two more from tipped passes at the line. Does his six interceptions then mean he's a good player?

In order to more effectively grade out players, Football Outsiders (FO) has developed a series of analytical tools that look beyond the basic statistics. Doug Farrar, who writes for Bear Report magazine, is a senior writer for FO and has crafted some outstanding pieces using these new analytical tools.

Recently, FO analyzed cornerbacks using a tool called "Success Rate." Success Rate, according to the Web site, is the percentage of passes that don't manage to get at least 45 percent of needed yards on first down, 60 percent of needed yards on second down, or 100 percent of needed yards on third down.

There are a bunch of other rules and caveats that apply to this analysis. It is far from an exact science, and the debate continues to rage as to the value of these newfound analytics, but as for a system that helps rank cornerbacks, this is as good as it gets. Read the full article here.

Whether or not you buy into Success Rate, everyone should find it interesting that Chicago's own Charles Tillman was the ninth worst cornerback in the league last year. Success Rate is only applied to corners who had 40 passes thrown to the man he was covering, of which there were 83 in 2010. Tillman ranked 75th out of those 83. Based on the criteria, Tillman only successfully stopped the opposing receiver 43 percent of the time when the ball was thrown his way.

Now obviously, this doesn't mean Tillman is awful. Too many times last season he was directed by the defensive coaches to line up seven yards off his receiver on a 3rd down and 3. In that case, the quick 3-yard hitch that picked up the first down really wasn't his fault. Also, safety play was not the Bears' strong point last season, meaning Tillman didn't always get the requisite over-the-top help he needs when playing the Cover 2.

Yet what this FO tool shows is too many receivers are having success when lined up across from Tillman. At 30-years old, he's no longer the spry, shutdown corner he once was. His value comes from his consistency and his ability to create turnovers. Which means Chicago's defensive coaches need to design a system that plays to Tillman's strengths.

If you do buy into the Success Rate tool, then it makes even more sense for Tillman to move out of the cornerback position and into the strong safety role. In this way, his run stopping abilities could be utilized while not having to risk putting him out on an island against the opposing team's best receiver every week.

It's safe to say he has at least a few more good years in him. But the Bears might want to start planning now for the inevitable time when Tillman is no longer worth the money, which could be sooner than later.

Jeremy Stoltz is Publisher of BearReport.com. To read him every day, visit BearReport.com and become a Chicago Bears insider.

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