The New York Jets enter Week 4 as the only team in the NFL with two divisional wins as they gear up to host the San Francisco 49ers. With CB Darrelle Revis injured for the remainder of the season, Gang Green will have to improvise on defense to replace the NFL leader in passes defended since 2007.

The 49ers suffered a surprising defeat in Minnesota last week. On defense, San Francisco allowed a Total QBR of 89.9 to Vikings quarterback Christian Ponder, their second-worst performance in the Total QBR era since 2007.

Of the 15 games scheduled in the NFL, this will be one of the two (Cowboys/Bears, MNF, ESPN) featuring opponents with winning records. Let's break down three statistical keys for this marquee matchup:

1. The Jets will have to defend a dynamic pass catcher in Vernon Davis, who is tied with Heath Miller for the NFL lead in touchdown receptions (four). Despite his position, Davis presents a deep threat as he leads qualified tight ends with an average target depth of 11.4 yards downfield. Meanwhile, the Jets have been physical with tight ends, holding them to 2.1 yards after catch, best among NFL defenses in 2012.

2. The 49ers have used a standard four-man pass rush on 79.7 percent of defensive plays since the start of last season, second in the NFL behind only the Eagles. Maximizing pressure with minimal personnel has allowed San Francisco to drop seven in coverage and disrupt passing lanes. From the start of 2011, the 49ers rank third in passes defended and lead the NFL with 21 interceptions when using four pass rushers or fewer.

Mark Sanchez could test that secondary. He leads the NFL with an average throw distance of 11.3 yards downfield against four or fewer pass rushers.

3. Alex Smith will face an aggressive Jets defense that ranks second in the NFL with added pressure on 42.4 percent of opponent dropbacks. Smith has been tops in the league against added pass pressure and trails only Robert Griffin III in Total QBR against five or more pass rushers. The Jets might need to change the game plan against Smith, especially without Revis to clamp down in the secondary.