Here are five nuggets of knowledge about Week 4:
Dansby homecoming: It has been two years since the Miami Dolphins outbid the Arizona Cardinals in free agency for linebacker Karlos Dansby. Miami needed an impact player and signed Dansby, a former Cardinal, to a $43 million contract in 2010. Dansby will play his former team for the first time Sunday when Miami travels to Arizona. The Cardinals (3-0) are one of the surprise teams in the NFL. The Dolphins (1-2) are rebuilding and trying to avoid a two-game losing streak. Dansby is hyped for his homecoming and called this a "must-win" game for Miami.
Tannehill's accuracy: One of the underlying struggles in Miami's offense has been the lack of accuracy from rookie quarterback Ryan Tannehill. The No. 8 pick was a 62.5 percent career passer in college. However, Tannehill has been off the mark in his first three NFL starts. Tannehill is completing just 52.9 percent of his passes, which included a 16-for-36 (44.4 percent) performance in Sunday's overtime loss to the New York Jets. Sometimes drops play a factor. But Tannehill also rushes his reads and stares down his receivers too often, which is typical for a rookie. Miami needs its quarterback to get better in those areas to take the next step.
Williams vs. Brady: The Buffalo Bills gave former Pro Bowl defensive end Mario Williams $100 million in free agency for games like Sunday's. Buffalo needs a big performance from Williams pressuring Patriots quarterback Tom Brady to pull off the upset at home. Williams is coming off his best game of the season, against the Cleveland Browns in Week 3. He recorded four tackles and 1.5 sacks. Williams had been mostly quiet until that point. Buffalo's defensive line appears to have a favorable matchup against New England. Brady already has been sacked seven times in three games.
Ridley's dry spell: New England starting running back Stevan Ridley started the season hot with 125 yards rushing in Week 1. But since then, Ridley has just 108 yards rushing the past two weeks. Ridley's opportunities are down, but so are his yards per carry. Ridley averaged just 3.5 yards per rush in losses to the Cardinals and Ravens. The second-year player needs to get back to his Week 1 form.
Run over: What has happened to the Jets' run defense? This was a group expected to be a top-five defense. Yet, through three games, teams are running through New York's front seven with unexpected ease. The Jets are 28th against the run, allowing 148.7 rushing yards per game. Their run defense will face another stern test Sunday against the San Francisco 49ers. Tailback Frank Gore has rushed for 264 yards and averages 5.9 yards per carry.