Even Bears fans undervalued Tillman for much of his early career, when fans were quick to point to his tendency to slip and fall in coverage once in a while.
Finally though, Bears fans began to come around and finally, the NFL community at large as Tillman was voted to his first Pro-Bowl after his ninth NFL season and quickly followed it up with a second consecutive Pro-Bowl and added an All-Pro appearance after last season.
However, through it all he has always had to endure backhanded compliments that merely point out his tendency to make a lot of tackles or "fit the defensive scheme perfectly."
Finally though, Profootballfocus.com has come out with an article diving into the numbers and proving once and for all that Tillman is more than just "the perfect cover-2 corner" but that he's among the best in the league:
What Cover-2 they do run protects him in that fashion, but he was thrown at more than enough when playing Quarters, Cover-3 or straight up Man coverage, with or without a single-high free safety to help out to have been tested deep. In 2011, his last full-season of play, the longest reception Revis allowed was 53 yards. Richard Sherman was beaten for a long of 56 yards this season, but the longest pass to get past Tillman was just 28 yards.
Comparisons to Richard Sherman and Darrelle Revis is about as high a compliment as can be bestowed upon an NFL cornerback.
Beyond that, PFF further dispels the idea that the Bears play a Cover-2 coverage the majority of the time:
People tend to think of the Bears as a Cover-2 team, one of the few still clinging to the Tampa-2 system by their fingernails under Lovie Smith, but in truth they ran far more Cover-3 than I would have imaged, and those were the plays that were getting Tillman in trouble, not because he couldn’t play like that, but because when quarterbacks recognized that coverage they simply threw short passes and picked up what that bail technique was giving them.
Of the 581 receiving yards he gave up last season, Tillman surrendered 327 of them when playing soft in a Cover-3 shell, usually with a bail technique as the Bears rotated to that coverage late. On 22 more targets, he gave up just 254 yards when playing either Cover-2, or man coverage.
So Tillman is a top CB and when he is allowed to get physical he can shut opponents down. In fact, the author argues that Tillman is actually hurt by the Bears' soft zone coverages. Look at the chart to see the completion percentage and reception numbers he allows when playing Cover-2 man vs. Cover 3/4:
Check out the full article and see the specifics about how Tillman shut down Calvin Johnson last season.
So there you have it, the Tillman Bears have known for years is finally getting league-wide respect. Let's hope he continues to play at the high level we've been accustomed to seeing over the years.