Dolphins RB Arian Foster announced his retirement in a written statement on Monday. "There comes a time in every athlete's career when their ambition and their body are no longer on the same page," Foster wrote. "I've reached that point ... I know it's not commonplace to do it midseason, but my body just can't take the punishment this game asks for any longer." Foster dealt with numerous injuries throughout his 8-year career, including a torn meniscus and a torn Achilles. He mustered just 2.6 yards per carry over between 2015 and 2016. RB Jay Ajayi, riding back-to-back 200-yard games, is locked in as Miami's feature back going forward. He'll be backed up by Damien Williams and Kenyan Drake.

Dolphins RB Damien Williams will start tonight, per beat writer Armando Salguero. Last week, Miami started Kenyan Drake in place of Arian Foster but saw 4 different RBs take handoffs. Williams finished with just 1 for 15 yards. Look for another committee approach tonight, making this a backfield to avoid.

NFL Network's Ian Rapoport says the Dolphins are "treating rookie RB Kenyan Drake as the starter today." That's a strange way to word it and comes as a surprise after most pegged Jay Ajayi to draw the start. Miami's coaching staff has obviously soured on last year's 5th-round pick, though. Expect multiple RBs to get on the field for the Fins today -- including Ajayi, Damien Williams and/or Isaiah Pead -- but Drake now looks like the best fantasy bet.

Dolphins RB Arian Foster (groin) has been ruled out for Sunday's game against the Browns. He didn't practice all week and certainly isn't a lock to return for Week 4. Jay Ajayi figures to serve as the lead back vs. Cleveland, but Kenyan Drake, Damien Williams and/or Isaiah Pead all figure to be involved as well. Ajayi is just a RB3 or flex option.

Dolphins RB Lamar Miller suffered an ankle injury in the 4th quarter of Sunday's game against the Jaguars.  He's considered questionable to return.  RB Damien Williams is next up on Miami's depth chart.

Dolphins RB Jay Ajayi is currently 4th on the Dolphins depth chart, according to insider Andrew Abramson.  The rookie is behind Lamar Miller, Damien Williams and LaMichael James.  GM Mike Tannenbaum recently called out Ajayi's pass protection, and beat writers have noted issues with his decisiveness and ball-security.  We're still intriguing by the 6'0, 228-pounder's potential, but it doesn't sound like he's a candidate for a significant early-season role.  That also means that Lamar Miller's role as feature back is safe.  HC Joe Philbin recently suggested that Miller's workload could grow this season.  We just updated our projections for the Dolphins backfield.

Dolphins insider Armando Salguero calls RB Lamar Miller (shoulder) "uncertain" for Thursday night's game against the Bills.  Miller was active this past weekend but played just 11 snaps and finished with only 4 carries and 1 catch.  He didn't record a touch in the final 10 minutes of the game.  The short week certainly isn't helping Miller's chances.  Even if he's active on Thursday night, he'll be an extremely shaky fantasy play against Buffalo's stout run defense.  Miami signed RB LaMichael James to the active roster on Monday.  He could mix in with Daniel Thomas and Damien Williams if Miller is out on Thursday.

Adam Beasley of the Miami Herald reports that Dolphins RB Lamar Miller is expected to play against the Lions today but in a more limited role than usual because of his shoulder sprain. Of course, none of us really knows just how much of the rushing workload will go to Daniel Thomas and Damien Williams, each a clear talent downgrade from Miller. The starter's decent passing-game use -- 2+ catches in 7 of 8 games -- helps his outlook. The shoulder and a bad matchup with the Detroit D pushes Miller toward the bottom of RB2 territory this week, but most of his owners will probably still have to use him in these bleak days on the fantasy RB landscape. Don't look to Thomas or Williams as fantasy options against Detroit unless you're truly desperate.

Dolphins RB Lamar Miller has been diagnosed with a sprained AC joint.  The team is calling him "day-to-day," but he's not a lock to be ready for this weekend's game against the Lions.  TE Jordan Cameron missed a game with the same injury, and Miller takes a lot more contact.  Don't expect him to practice much this week, and he might end up as a game-time decision.  If Miller can't go, RBs Daniel Thomas and Damien Williams would likely share backfield duties.  Neither would be more than a low-end RB3 against Detroit's stout run defense.