FBO: Numbers crunching, Week 10

Time to dance again, boys. Getty Images

Each week, Football Outsiders looks at every matchup on the NFL schedule and pulls out interesting statistical trends for fans. We call it "Numbers Crunching." Much of the analysis is based on DVOA, which takes every single play during the season and compares it to the league average based on situation and opponent. DVOA and Football Outsiders' other advanced stats are explained here. Without further ado: the Week 10 previews.

Thursday night game

Chicago Bears at San Francisco 49ers

Strange timing split of the week: San Francisco has the league's top defense in DVOA in the third quarter -- but ranks 16th in the first half and 22nd in the fourth quarter.

The 49ers rank just 31st in Football Outsiders' Adjusted Line Yards stats, and Frank Gore gets a lot of yards on his own thanks to breakaway runs. However, there's one place where the 49ers are good blocking and consistent gains: runs around left end. Our stats rank them seventh on those runs. That happens to be the weakness of the Chicago run defense, which ranks 15th in ALY overall but 24th against runs around left end.