Some of the quarterback's most valuable contributions -- changing plays at the line of scrimmage, for instance -- have been tough to quantify.
Coach Jim Harbaugh called Smith "elite" and promoted him for the Pro Bowl last season. Supporters could always point to Smith's No. 9 ranking in NFL passer rating for 2011 (90.7 set a career high for him) even while Smith and Harbaugh discounted raw stats as a meaningful way to measure quarterback performance.
That was all fine, but money trumps talk and stats. And when Smith became a free agent last offseason, the 49ers let him test the market, something teams almost never allow franchise quarterbacks to do. Smith ultimately commanded a game manager's contract from the 49ers, a three-year deal giving the team an out after only one season.
Despite that No. 9 ranking in passer rating, Smith ranks 20th among NFL quarterbacks in compensation for this season. That salary ranking lines up closely with Smith's No. 22 ranking last season in Total QBR, the metric ESPN developed to take into account a fuller measure of a quarterback's contributions.
Players with high NFL passer ratings and relatively low QBR scores generally aren't asked to carry their offenses. They're efficient passers, but not the most valuable quarterbacks. They're more apt to sign modest contracts.
That was the case for Smith last season.
Times could be changing.
Smith leads the NFL in passer rating and Total QBR through five weeks this season. That suggests he's carrying more of the offensive load for the 49ers, something we saw most demonstrably during a 45-3 victory over Buffalo on Sunday. Smith completed 18 of 24 passes for 303 yards and three touchdowns, including two on throws well down the field.
Football is, of course, a team game. A quarterback surrounded by superior talent enjoys significant advantages.
Eli Manning, another quarterback outranking Smith on the NFL pay scale, will be on the other sideline when the New York Giants visit Candlestick Park in Week 6. We'll have much more to discuss after that one.
With that, let's take a look at how NFC West passers graded out for Week 5 in relation to Total QBR, with NFL passer ratings in parenthesis as a reference point (thanks to ESPN Stats & Information for the charting info):
Alex Smith, San Francisco 49ers (99.2 QBR, 156.2 NFL rating): Smith completed 18 of 24 passes (75 percent) for 303 yards with three TDs, zero INTs, zero sacks and zero fumbles. He rushed three times for 49 yards. Smith was much better at home than on the road last season. He has shown improvement on the road this season and was nearly perfect against Buffalo in only his second home game of the season. The 49ers have their next two games at home. A potentially sprained finger on Smith's throwing hand was the only negative for him Sunday.
Russell Wilson, Seattle Seahawks (51.7 QBR, 82.3 NFL rating): Wilson completed 19 of 25 passes (76 percent) for 221 yards with one TD, two INTs, two sacks and zero fumbles. He rushed five times for 12 yards. Wilson needed strong backing from his defense to win this game after Carolina returned one of his two interceptions for a go-ahead TD in the second half. Overall, though, Wilson made clear progress. Seattle appeared to have actual weapons on offense for stretches of this game, a departure from recent form. Sidney Rice played with flair. Golden Tate's big-play ability showed up on a 13-yard catch-and-run for a TD, and on a 56-yard reception wiped out by penalty. The Panthers sent five or more pass-rushers on only six plays, the fewest Wilson has faced this season (St. Louis 8, Dallas 7). Wilson completed 3 of 4 passes for 36 yards with one INT and one sack against this added pressure.
Sam Bradford, St. Louis Rams (38.6 QBR, 69.7 NFL rating): Bradford completed 7 of 21 passes (33 percent) for 141 yards with two TDs, one INT, one sack and no fumbles. He netted zero yards on five rushes. Bradford started quickly, making aggressive throws on deep passes as St. Louis took an early lead. A miscommunication with Danny Amendola killed one drive, however, and Bradford struggled once an injury removed Amendola from the game. Bradford completed 3 of 9 passes for 66 yards with two TDs, one INT and a sack on third down. He had a 15-yard scramble on a third-and-15 play wiped out by penalty. This was an ugly game, but one the Rams generally controlled.
Kevin Kolb, Arizona Cardinals (24.3 QBR, 72.8 NFL rating): Kolb completed 28 of 50 passes (56 percent) for 289 yards with zero TDs, zero INTs, nine sacks and one lost fumble. He rushed once for two yards. Kolb somehow held up physically despite taking a beating that left him with a bloody mouth. When Kolb did have time, he missed at least two open receivers for what could have been big plays. His receivers too frequently failed to hold up their end when Kolb did deliver the ball accurately. Even Larry Fitzgerald dropped a pass.
The chart below shows how quarterbacks from games involving NFC West teams fared in Total QBR for Week 5, provided they played enough to qualify for inclusion.
The column showing point above average reveals the "number of points contributed by a quarterback over the season, accounting for QBR and how much he plays, above the level of an average quarterback."