Lots of uncertainty at running back for Miami Dolphins
![Lots of uncertainty at running back for Miami Dolphins](http://bloximages.chicago2.vip.townnews.com/lacrossetribune.com/content/tncms/assets/v3/editorial/6/09/60964bf2-ba42-5c9f-a3ce-766574878751/579fab19bbd12.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.