Four seasons into his career Felix Jones has concerned the Dallas Cowboys in a lot of ways—primarily in his struggles to stay on the field—but they rarely had to worry about his ability to run really fast on really short notice; in 458 attempts he's averaged 5.1 career yards per carry since being their first-round pick back in 2008. In the 2012 preseason, however, he's looked out of shape and mediocre according to most observers; most recently he got a Jerry Jones vote of confidence, which is the kind of thing you don't really want to need.
His roster spot—if you believe Jerry—isn't in doubt, but Felix Jones's performance as the Cowboys' change-of-pace back is one of the things most worth watching when the St. Louis Rams take them on in Pretend Week 3. Felix Jones is never going to carry a heavy workload, but at 25 he should still be looking for another gear as a dynamic offensive weapon, not struggling to stick around as their backup running back.
Rams fans will probably be busy watching Sam Bradford try to connect with his wide receivers and Jeff Fisher connect with his defense, but if the Cowboys offense catches your eye you could do worse than to see whether Felix Jones looks anything like then Felix Jones you remember.