Seattle Seahawks rookie Russell Wilson leads the NFL in Total QBR after Week 5.

That is a stunning achievement given that Peyton Manning, Tom Brady, Aaron Rodgers and Robert Griffin III rank second through fifth, respectively.

Wilson ranked only 29th through Week 5. He had five touchdowns, six interceptions and a 33.9 QBR score to that point in the season.

Since then, Wilson has completed 63.5 percent of his passes for 1,529 yards with 14 touchdowns, two interceptions, 13 sacks and 13 first downs rushing. Those and other factors leave Wilson with an 83.0 QBR score over that span. Wilson is now at 65.3 for the season, right near the cutoff for Pro Bowl-caliber play over a full season.

Manning leads the NFL this season at 81.1 out of 100, with 50 right around average.

Anyone watching Wilson lead 97- and 80-yard touchdown drives to beat the Chicago Bears on Sunday knows Wilson played spectacularly. The Bears led the postgame applause. There was no surprise in seeing Wilson emerge from that game with an 85.4 QBR score for the game. He was that good.

San Francisco's Colin Kaepernick wasn't nearly as good during the 49ers' 16-13 defeat at St. Louis. A case could be made that he cost his team the game with a poor decision leading to a safety and a botched pitch. That is why I was quite surprised to see QBR reward Kaepernick with an 82.4 score Sunday.

Dean Oliver, Albert Larcada and Michelle Sastri of ESPN's analytics team pointed to positive plays Kaepernick made and limitations in the NFL's official game charting system in explaining the surprising figure. Those limitations affect very few plays to this degree, but they significantly limited how much blame Kaepernick received for his role in a costly errant pitch to Ted Ginn Jr.

Among the highlights from their responses:

Scramble huge: Kaepernick's 50-yard scramble to the St. Louis 14-yard line increased the 49ers' win probability from 57.1 percent to 80.9 percent. His in-game QBR score spiked from 67.0 to 89.3 because the situation was so important and because Kaepernick, not a receiver, accounted for the gain. This was the fourth-longest scramble by a quarterback since 2008.

Still expected to win: The fumble and ensuing touchdown return by the Rams' Janoris Jenkins dropped the 49ers' win probability from 90.3 percent to 61.7 percent. The 49ers were still favored to win because the Rams needed a two-point try to tie.

Shared blame: Kaepernick didn't make critical mistakes after the 50-yard scramble. The holding penalty against tight end Delanie Walker was a killer play. That penalty helped the Rams get the ball back with 1:34 remaining. A penalty against the 49ers' Dashon Goldson for unnecessary roughness with 1:07 remaining was also critical because the Rams' kicker, Greg Zuerlein, is such a threat from long range.

Strange situation: QBR relies, in part, on official play-by-play data from the NFL. The league scored Kaepernick's fumble as an aborted play, disregarding the role Kaepernick's errant pitch played in the turnover. As a result, QBR did not "blame" Kaepernick as much as it would have blamed him ideally. This will happen in rare cases, skewing the QBR score for a single game.

Similar situations: The NFL play-by-play accounted for Kaepernick's fumble the same way it accounted for a Week 3 fumble on a pitch from Washington's Robert Griffin III to Brandon Banks. Kaepernick's pitch was off-target. The one Griffin delivered appeared perfect. Kaepernick was mostly to blame for the 49ers' fumble. Banks was mostly to blame for the Redskins' fumble. Yet, the official play-by-play accounted for those plays in the same manner, as aborted plays.

I would expect ESPN's analytics department to seek ways around these sorts of abnormalities.

"We are looking into additional tracking going backward and forward to correct this illogicality, but don’t have it in place yet," Larcada said.

With that, let's take a closer look at NFC West quarterbacks in relation to Total QBR for Week 13:

Russell Wilson, Seattle Seahawks (85.4 QBR, 104.9 NFL rating). Wilson completed 23 of 37 passes (62.2 percent) for 293 yards with two touchdowns, zero interceptions, two sacks, 13 passing first downs and a 10.6-yard average pass length (8.8 was average for Week 13). He had nine rushes for 71 yards and five rushing first downs. He had no turnovers and even recovered a teammate's fumble about 10 yards downfield. Seattle used the read-option play during the fourth quarter and overtime to a degree they had not done previously. I'll take a closer look at that as time permits.

Colin Kaepernick, San Francisco 49ers (82.4 QBR, 83.9 NFL rating). Kaepernick completed 21 of 32 passes (66.7 percent) for 221 yards with zero touchdowns, zero interceptions, three sacks, 11 passing first downs and a 5.8-yard average pass length. Kaepernick ran nine times for 84 yards and two rushing first downs.

Sam Bradford, St. Louis Rams (59.8 QBR, 81.3 NFL rating). Bradford completed 26 of 39 passes (66.7 percent) for 221 yards with zero touchdowns, zero interceptions, two sacks and 10 passing first downs. He had three rushes for 31 yards and two first downs. Bradford's scrambles were timely. His QBR score was respectable, particularly given that Bradford was playing without top receiver Danny Amendola, who had burned the 49ers repeatedly when the teams faced each other previously.

Ryan Lindley, Arizona Cardinals (3.0 QBR, 28.0 NFL rating). Lindley completed 10 of 31 passes (32.3 percent) for 72 yards with zero touchdowns, one interception, two sacks and a 10.1-yard average pass length. He had zero rushes. The average pass length stands out as quite long for a player with minimal experience. I haven't watched this game closely yet, but it seems as though the Cardinals could help out Lindley by having him throw shorter passes.

2012 Relevant NFC West QBR Ranks: Week 13