For the fourth consecutive year, the will enter the season as the heavy favorites due to a stacked roster. They aren't without question marks, however, foremost of which is 's ability to recapture the form he showed in the first half of the 2014 season. Should Manning falter, the and are strong enough to take advantage. The are finally building a nucleus of young talent, but are still years away from serious contention. Our series will rank each team by the strength of their roster. 1. Denver Broncos What's changed: Despite a wildly impre sive 46-18 record over four years, coach John Fox was dumped in favor of Gary Kubiak, who brought along long-time defensive coordinator Wade Phillips. The Alexander Petrovic Jersey offense that broke a slew of records in 2013 will have a different look, as veteran and second-year wideout are slated to replace tight end and slot machine , respectively. Outside of the lo ses of run-stuffer and free safety , the defensive personnel remains largely intact. The big change is the shift from Jack Del Rio's 4-3 defense to Phillips' 3-4 scheme. Unlike most teams, the ' personnel is already well-suited to the new system. What's next: 2. San Diego Chargers What's changed: The to Los Angeles has spooked, leaving the with one of the offseason's . Although the team's stated preference is to via a , Oregon's Marcus Mariota looms as an . If Rivers stays, he will be throwing to a pair of new targets in veteran wide receivers Stevie Johnson and . Even with the addition of jumbo guard , pa s protection remains a question mark following the retirements of veterans and and the release of guard . The backfield is similarly in turmoil after early-down hammer landed in Philadelphia. What's next: 3. Kansas City Chiefs What's changed: Shortly after conceding that a historically inept receiving corps , general manager John Dorsey dumped the trio of , and . He succeeded in recruiting as Bowe's replacement, reuniting the former receiver with Andy Reid. Now that veteran has been released, is expected to play a featured role in the revamped aerial attack. The offensive line has a new look as well. After center defected to Oakland, the responded by trading for guard and signing . It remains to be seen if this unit is an upgrade on last year's, which struggled to maintain consistency. What's next: 4. Oakland Raiders What's changed: Gone are interim coach Tony Sparano, offensive coordinator Greg Olson and defensive coordinator Jason Tarver, replaced by Jack Del Rio, Bill Musgrave and Ken Norton Jr. The high-dollar signings of center and blocking specialist suggest Musgrave plans to run a smash-mouth attack to complement second-year quarterback . One year after the signed a bevy of over-the-hill veterans to bolster the defense, the majority were jettisoned in favor of another batch of free-agent additions headlined by nose tackle , middle linebacker and safety . General manager Reggie McKenzie desperately needs a second consecutive strong draft haul so he can put a halt to Oakland's annual parade of free-agent disappointment. What's next: The latest Podcast and breaks down the biggest rumors and storylines. Find more content on . Andy Moog Jersey