According to Miami Dolphins beat writer Andrew Abramson, running back Damien Williams is still currently the leader for the Dolphins backup job behind Lamar Miller.
LaMichael James is also in the mix, but both backs are considerably ahead of rookie Jay Ajayi. Williams posted a 3.4 yard per carry during his rookie season.
Williams posted a poor -5.94 Rushing Net Expected Points on 36 carries for the Dolphins last season. However, Williams performed well in the passing game ranking 19th among running backs with a 18.08 Reception NEP. We project Williams to finish the year with 216 rushing yards, one rushing touchdown, 19 receptions, 173 receiving yards, and one receiving touchdown.
Source: Andrew Abramson, Twitter