Lots of uncertainty at running back for Miami Dolphins
![Lots of uncertainty at running back for Miami Dolphins](http://bloximages.chicago2.vip.townnews.com/tdn.com/content/tncms/assets/v3/editorial/b/bf/bbfecd05-b314-587d-ae19-5d7e48eb1f31/579faaca27eaa.image.jpg?resize=300%2C213)
DAVIE, Fla. (AP) — Miami Dolphins practice began Monday with first-team running back Jay Ajayi on the sideline, riding a stationary bike and making it harder for the team's ground game to get rolling.