PHOTO: Redskins' Ryan Clark wears No. 21 at OTAs to honor Sean Taylor

Washington Redskins safety Ryan Clark turned up at OTAs wearing a different number than his usual 25. 

The two played together in Washington during the 2004 and 2005 seasons before Clark moved on to Pittsburgh. 

Taylor was tragically killed at the age of 24 during a home invasion in 2007 and his number remains unofficially retired by the team, as the Redskins don't retire numbers.