Stunning achievement for Cards' defense

The 2012 NFL season is not a total loss for the Arizona Cardinals.

Their defense continues to force opposing quarterbacks into mistakes while holding them well below their usual performance levels.

2012 Total QBR by Opponent

The 12 primary quarterbacks Arizona has faced to this point in the season have combined to complete 54.5 percent of their passes with 16 touchdowns, 21 interceptions and a 33.3 Total QBR score against the Cardinals.

Those same quarterbacks have completed 62.8 percent of their passes with 212 touchdowns, 112 picks and a 61.2 QBR score against everyone else.

The chart lists those 12 quarterbacks by QBR differential.

Matthew Stafford, Tom Brady, Matt Ryan and Russell Wilson have combined for three touchdowns, 11 picks and a 23.4 QBR score against Arizona. They have 92 touchdowns, 33 interceptions and a 74.8 QBR score against everyone else.

These are stunning achievements for defensive coordinator Ray Horton, his staff and the Cardinals' defensive players. The Arizona offense has done almost nothing to help them. In fact, the offense has repeatedly put the defense in tough situations.