DETROIT LIONS (7-9)Week 16: Detroit Lions at Dallas Cowboys, (Mon.) 7:30 p.m. - ESPN (Full schedule)ALLEN PARK, Mich. -- Calvin Johnson's retirement leaves a huge void for the Detroit Lions.Detroit will face defenses for the first time in a decade without one of its players drawing double coverage on almost every snap.Johnson walked away from the Lions and the league in March, announcing his retirement at the age of 30.