Cowboys sign speedster Teddy Williams

SAN ANTONIO -- Teddy Williams hasn't played football in five years, but the Dallas Cowboys signed him Thursday.

The Cowboys will give the 22-year-old former Texas-San Antonio track star a shot to play defensive back.

The 6-foot-3, 198-pound Williams was a four-time All-America sprinter. He ran a wind-aided 9.90-second 100 meters in 2009 and has reportedly been clocked at 4.31 seconds in the 40-yard dash.

Williams, who worked out for the Cowboys earlier this week, last played football as a wide receiver at John Tyler High School in Tyler, Texas. Williams' high school football career ended when he broke his ankle in the fourth game of his senior season.

The Cowboys cut punter/kicker Delbert Alvarado, an undrafted rookie, to make room for Williams.

Tim MacMahon covers the Cowboys for ESPNDallas.com. You can follow him on Twitter or leave a question for his weekly mailbag.