QBR and T.J. Yates' work against Colts

Our look at how the quarterbacks of the AFC South performed in Week 16:

This week’s question out of those numbers for me is, why the discrepancy between T.J. Yates' QBR and passer rating?

Here’s the explanation from John McTigue of ESPN Stats and Info:

"Yates was 5-for-5 on third down, but only one of those completions went for a first down. Yates averaged just 1.8 air yards per pass attempt on third down, despite needing at least 5 yards on four of the five attempts. Yates was also sacked once on third down.

"Although it didn’t lead to points, Yates lost a fumble on a Robert Mathis sack early in the first quarter, setting up the Colts with a first-and-10 in Texans territory. The game was obviously still in [question] at the time, and had a negative impact on his QBR.

"Half of Yates’ passing yardage came in the air and half came after the catch. QBR gives more weight to the quarterback when passes have more air yards.

"Yates’ two best QBR games this season came when more than half of his passing yards were in the air. His three worst games were when at least half of his yards came after the catch."