Ryan Williams will now be the featured back for the Arizona Cardinals and while it might look like a good idea to start him in fantasy leagues in Week 4, fantasy owners should wait another week to do so.
After Beanie Wells was placed on the injured reserve list (per ESPN.com), Williams instantly became the No. 1 back in Arizona.
Williams didn't contribute much the first two weeks of the season, but in Week 3, the Cards' back had 83 yards on 13 carries, good enough for 6.4 yards per rush.
In Week 4, Arizona will be up against a tough run defense in the Miami Dolphins. Miami is currently ranked third in the NFL against the run, allowing 66 yards on the ground per game.
The Dolphins will no doubt make it tougher for Williams to gain yardage on the ground like he did last week against the Philadelphia Eagles' 17th-ranked rush defense.
To make matters worse for the Cardinals' running game, Williams might not be at full strength on Sunday.
Arizona's new No. 1 back is being listed as probable for the Week 4 showdown as he battles a knee injury. If his knee problems continue in this game, Williams won't be as explosive as usual and that could leave his production lacking.
If that's the case, the Cardinals might eradicate their rushing attack altogether and instead, depend on Kevin Kolb to get the job done. While that might have been unthinkable just a few weeks ago, Kolb has been playing better of late and could conceivably try to win this game with his arm alone.
Not to mention, the Cards won't force the issue with Williams since they have LaRod Stephens-Howling and William Powell to distribute the carries to as well.
A top rush defense and a nagging injury could slow Williams down this week and that makes it a safe bet to start another running back over him for Week 4.