It may be a fluke. He may flame out. But rushing for 253yds...thus breaking the team record...in your very first start...is worth 'noticing' in and of itself bro. He was a 3rd string RB. He is now being strongly looked at for featured back.
Again, for me, the defense has to be considered. I start him this week against Philly but my expectations are tempered because:
a. Philly ain't St. Louis
b. Andy Reid game plans almost as well as Belichick after a bye.
Think Jerome Harrison back in '99.
Played well for the remainder of the season after his historic day (winning many people a fantasy title, yours truly included), named starter, lost the gig to Hillis, shipped to the Eagles.

It's one game. If this were a research project, the sample size is too small. And, unlike Harrison, he does Jones with which to contend and possible durability issues. It was one game--a GREAT, GREAT game but just one.