Inside Troy Smith's unsustainable numbers

The San Francisco 49ers are 2-0 with Troy Smith at quarterback, even though they've struggled on third down.

Smith and the 49ers failed to convert even once in 11 third-down opportunities Sunday against the St. Louis Rams. But they still won the game, 23-20.

How can this be?

The answer shines through in Smith's numbers on other downs.

2010 Troy Smith by Down

Smith's first-down numbers are extraordinary. They jumped off the sheet when I was running postgame calculations based on charting.

Overall, Smith is averaging 11.7 yards per attempt with a 116.6 rating.

The second chart breaks down Smith's efficiency by down and personnel group. These yards-per-attempt numbers are unsustainable. Eventually, Smith will need to become more efficient on third down to keep drives moving.

2010 Troy Smith Splits

Note: Personnel names reflect running back and tight end counts. For example, "12" personnel features one running back and two tight ends. "3TE" plays encompass those with three tight ends and either one or two backs. Stats are sorted by passer rating.