Five nuggets of knowledge about Week 5:
Seahawks' rare opportunity: A Seattle Seahawks victory at Carolina would give all four NFC West teams a winning record through Week 5 for the first time since the NFL realigned into eight four-team divisions in 2002. The Arizona Cardinals (4-1) and St. Louis Rams (3-2) have already played. The San Francisco 49ers (3-1) will be above .500 no matter what happens against Buffalo on Sunday. NFC West teams had 10 combined victories through Week 8 last season. They already have 12 this season even before the Seahawks (2-2) and 49ers play their Week 5 games.
Defending Alex Smith: The 49ers' quarterback was generally exceptional at home last season. His Total QBR score at Candlestick Park (76.1 out of 100) was 42.3 points higher than it was on the road (29.3). That was the largest point differential in the NFL. The 49ers play at home Sunday for only the second time in five games this season. Despite the heavy road schedule, Smith enters this game against Buffalo with an overall QBR score 30.1 points higher than it was last season. Only three teams have realized larger gains from last season and only one, Cincinnati, has done so with the same quarterback behind center. Smith is at 66.8 on the road, 79.4 at home and 69.8 overall, which ranks eighth in the NFL. No wonder absolutely no one is asking when Colin Kaepernick might take over.
What a rush: Quarterbacks dominate headlines. Rushing attacks could dominate remaining NFC West games for Week 5. The 49ers rank second (5.4) and the Bills fourth (5.1) in yards per rushing attempt this season. The 49ers are second on first down at 5.1 per carry (the Bills lag at 3.9). The Bills are first (7.0) and the 49ers second (6.2) on second-down rushes. Meanwhile, Seattle's Marshawn Lynch leads the NFL in rushing yards, not only this season but since Week 9 last season. Carolina's Cam Newton ranks second to Robert Griffin III in rushing yards by a quarterback with 167 (5.1 per carry). The Panthers rank fourth in team rushing yardage since the start of last season. Seattle and San Francisco emerged from Week 4 ranked among the NFL's top five in fewest yards per carry allowed.
Going small on defense: The Bills run their offense primarily from personnel groupings featuring three or more wide receivers. They lead the NFL with 591 rushing yards against defenses featuring additional defensive backs. They rank fourth in yards per carry on these attempts (6.3). The 49ers are allowing only 3.4 yards per carry on 45 attempts with their nickel and dime defenses. The rest of the league allows 4.9 yards per carry on these rushes.
Russell Wilson's history: The Seahawks' rookie quarterback had three passes intercepted during a 19-13 defeat at St. Louis last week. It was the first three-pick game of his NFL career and only the third time he's thrown more than two in 50 college games and four in the NFL. Wilson had only seven games with more than one interception during his college career. The multipick games came in bunches. There were three in a five-game span in 2009 and three in a row during the 2010 season. Wilson transferred from North Carolina State to Wisconsin for the 2011 season. He threw only four picks all season, two against Michigan State.
Note: ESPN Stats & Information contributed to this item.