In July 2009, Williams began playing on the Memphis Grizzlies Summer League team in Las Vegas, Nevada. He joined 2009 first-round pick Hasheem Thabeet, undrafted rookie free agent Jeff Adrien, and Rudy Gay as one of four former UConn Huskies on the Grizzlies' Summer League roster. On August 7, 2009, Williams officially signed with the Grizzlies.