Steelers keep David Johnson

The Steelers have re-signed tight end / fullback David Johnson to a one-year contract, Bob Labriola of Steelers Digest reported Tuesday. Johnson missed the 2012 season after suffering a torn anterior cruciate ligament in August. The 6-foot-2, 260-pound Johnson has primarily served as a blocker for Pittsburgh. He has appeared in 47 games, starting 24…