I think he will struggle against any team with a decent defense. With a one dimensional offense, it doesn't take much to stop the run. For the record, San Diego and Cleveland don't count as decent defenses.
That aside, 500 yards and 4 TDs 3 weeks in isn't too bad is it? He'll come back down to earth next week against KC, but he is an every week starter unless you have Portis and Priest as your two starters.