DAVIE, Fla. (AP) – Veteran running back Larry Johnson has signed with the Miami Dolphins after sitting out most of last season.  Johnson gained 2 yards on five carries in two games before he was released by the Washington Redskins last September.  The 31-year-old has rushed for 6,221 yards and 55 scores in his career, but has played in just 16 games in the past three seasons.  In 2009 Johnson was released by the Kansas City Chiefs in November and finished the year with Cincinnati. His time in Kansas City was marred by off-field problems, including two suspensions in his final 12 months with the team.  Johnson’s best years were in 2005-06 with the Chiefs, when he had consecutive 1,750-yard seasons.  The Dolphins waived running back Kory Sheets.