"The Baltimore Ravens have a soft real-and-fake grass mix at their training facility in Owings Mills, Md., called SportGrass. No player likes to be timed on SportGrass, preferring the faster track of a tartan track or artificial turf. But the Ravens have used the surface to time players for the 40-yard dash for several years, and it usually results in a time about two-tenths of a second slower than the time a player would run on a track or pure artificial turf. When 29-year-old Donte' Stallworth worked out for the team early last week, he stepped foot on the SportGrass and ran a 4.40-second 40. It's the fastest time recorded on the turf by the club. "