Stafford was drafted with the 13th overall pick by the Buffalo Sabres in the 2004 NHL Entry Draft. He started his professional career playing with the Sabres' AHL affiliate, the Rochester Americans. During his time in the AHL, Stafford played for Planet USA during the AHL All-Star Classic in 2006-07. On June 3, 2011, he signed a 4 year, $16 million contract extension with the Sabres.