Cowboys rookie WR Terrance Williams undergoes concussion test

Cowboys rookie wide receiver Terrance Williams was shaken up during Friday’s practice and underwent a concussion evaluation, Calvin Watkins of ESPNDallas.com reported. DallasCowboys.com suggested that Williams could potentially miss the club’s first two preseason games: Sunday’s meeting with Miami in Canton, Ohio and Friday’s contest at Oakland. A third-round pick from Baylor, Williams is listed as second-string…