There's not a lot of recent history with Colts players wearing No. 21. Teddy Williams, Kevin Thomas and Bob Sanders are the players to most recently wear that number, according to Colts.com
Sanders is the marquee player to wear No. 21. He was named NFL Defensive Player of the Year in 2007. Sanders' problem is that he couldn't stay healthy. He was limited to only eight games total in his final two seasons with the Colts.
Davis doesn't have health issues. He has consistency issues. He has the talent. It's a matter of playing hard every game. Davis had 46 tackles, 12 passes defended and an interception last season.