The rest of the AFC should be worried, because the Oakland Raiders are lurking. The organization once led by the great Al Davis made massive improvements through the first two days of free agency.
With the additions of cornerback Sean Smith, linebacker Bruce Irvin and guard Kelechi Osemele (even more names could eventually be added), Raiders general manager Reggie McKenzie added three key components while spending $135.5 million in total contract value during the first 24 hours of the new league year.
Each of these pieces add to a team that improved to 7-9 last season under the direction of first-year head coach Jack Del Rio, the team's most wins since the 2011 campaign in which the Raiders finished 8-8 overall under Hue Jackson.
More importantly, three performers established themselves as legitimate building blocks last year.
Derek Carr started his ascension toward franchise-quarterback status. The second-year signal-caller threw for 3,987 yards, 32 touchdowns and only 13 interceptions.
While Carr improved, the team's 2014 NFL draft pick, Khalil Mack, rocketed toward superstardom. The former fifth-overall pick finished second overall behind the Houston Texans' J.J. Watt with 15 quarterback sacks. According to Pro Football Focus, Mack also finished as the league's best run defender among edge players.
McKenzie hit a home run with Carr and Mack in the same draft class. The general manager was still on point when he selected wide receiver Amari Cooper with the fourth overall pick in the 2015 NFL draft. The Alabama product led all rookies with 72 receptions and 1,070 yards. Due to his exceptional first-year performance, Cooper earned his first Pro Bowl berth.
Teams build through the draft. This is what the Raiders have done successfully over the last two years. Free agency, meanwhile, is an opportunity to accentuate a roster.
With Carr, Cooper and Mack in place, the Raiders continue to build around those key pieces while freely spending in free agency to acquire multiple quality starters.
Sean Smith
Oakland's most recent signing serves as a double bonus.
Smith will be a welcome addition to the team's secondary. Last year, T.J. Carrie solidified one cornerback position, but the Raiders continued to search for a legitimate bookend. David Amerson played well when called upon, but he isn't the team's long-term answer. The D.J. Hayden experiment as a starter finally appears to be over after three disappointing seasons.
With uncertainty at the position, Smith can walk in from day one and provide a stabilizing presence. The 28-year-old cornerback proved to be one of the NFL's most consistent performers over his career, as Pro Football Focus' Nathan Jahnke noted:
The former member of the Kansas City Chiefs also brings length and a physical style of play for defensive coordinator Ken Norton Jr., who was hired away from the Seattle Seahawks and wants to press on the corners.
Not only will Oakland improve with Smith on an island, but the Chiefs are now worse because he's not in the lineup.
Marcus Peters earned AP Defensive Rookie of the Year honors, but part of his success derived from the symbiotic relationship with Smith as his bookend. The Chiefs aren't a better team without the veteran cornerback in the lineup, because he helped make Bob Sutton's defense thrive.
Thus, the Raiders improved while one of the team's primary rivals is a little bit worse than it was a week ago.
Bruce Irvin
Irvin's decision to quickly sign with the Raiders came as a surprise. It really shouldn't have. The linebacker spent his first three seasons playing under Norton in Seattle. The two reunited in Oakland, and it's Mack who should be smiling from ear to ear.
Last season, Oakland lacked a true pass-rush threat opposite their second-year stud. Weak-side linebacker Malcolm Smith actually finished second on the team with only four sacks and wasn't asked to rush from the edge. Malcolm Smith primarily served as a blitzer in those situations.
Norton needs a much more consistent presence opposite Mack. The organization appears to have found it in Irvin, according to Jahnke:
The West Virginia product's inclusion will allow Mack to develop in his role as a defensive end. Irvin can serve as the team's "Otto," who doubles as the team's "Sam" backer and third-down pass-rusher.
Oakland also gets much more athletic along its second line of defense. The 28-year-old defender can drop into space, rush the passer and chase down ball-carriers.
In the NFC West, the Chiefs and Denver Broncos dominate with a pair of fearsome pass-rushers. The Raiders now have their own pair in Irvin and Mack.
Kelechi Osemele
An offensive lineman is never considered a sexy addition to any team. However, the Raiders landed arguably the top blocker on the market when they secured Osemele's services.
This is especially important on a few fronts.
First, the former member of the Baltimore Ravens is an elite guard and should stabilize the right side of the line if he stays along the interior. Osemele and Gabe Jackson would form the league's most physical guard duo.
If the Raiders can't find a way to address left tackle in the coming days, the Iowa State product can also move to the blind side. Last season, Osemele started the final four games of the 2015 campaign at left tackle and he performed admirably. At $11.7 million per year, this might signal a permanent change to tackle.
With Osemele potentially at left tackle, he and Jackson could form an absolutely devastating combination on that side of the offensive line. When the Raiders need a crucial yard or two, everyone will know exactly where they'll run the ball.
Why?
Because Osemele is one of the league's nastiest run-blockers. He will attempt to bury anyone in his way.
OL Watchdog provided an example on social media:
Last year, a preseason injury to Menelik Watson forced the Raiders coaching staff to juggle its offensive line, particularly on the right side. With Watson returning and Osemele's addition, Oakland's starting five up front is nearly solidified.
But one more lineman could still be added to the mix.
More additions?
Sean Smith, Irvin and Osemele are only the initial moves in this year's free-agent chess match. More could be on the way.
The reason Osemele might be forced to play left tackle, for example, is that last year's starter, Donald Penn, remains available in free agency.
The 32-year-old blind-side protector started 32 straight games for the Raiders and expressed a desire to return for his 12th season.
"I’ve been open with my plan. My plan is to be a Raider," Penn said via Bay Area News Group's Jerry McDonald before free agency officially began. "We’re trying to figure out if the feeling is mutual. They tell me it is."
Penn will draw interest from other teams due to his dependable play at a premium position, but his stance is clear. The Raiders don't need to rush into an agreement. However, the organization's ability to retain the reliable veteran will only make its line and overall offense even better.
Another veteran the Raiders continue to pursue is three-time Pro Bowl safety Eric Weddle. Much like Penn, there appears to be mutual interest from both parties, according to John Middlekauff of 95.7 The Game in San Francisco.
One of the new Raiders is already recruiting Weddle to Oakland:
The potential additions of both Penn and Weddle along with the team's recent acquisitions could help push the Raiders out of mediocrity into legitimate playoff contention.
AFC Best
Oakland faces an uphill battle in the AFC West. The division features the reigning Super Bowl champion Broncos and the Chiefs, who won 11 straight games before being bounced out of the playoffs by the New England Patriots.
However, the Raiders are a much more complete team today than they were last week.
McKenzie's roster no longer features a few young players who will be forced to carry the team because it lacks legitimate surrounding talent. The general manager wisely paired some of his best young players—Mack, Carrie and Jackson—with veterans still in their primes who will help develop those around them into next-level performers.
Sean Smith, Irvin and Osemele are tremendous standalone additions, but it's how they fit into the Raiders' overall plans that should have the organization and its fanbase truly excited for the team's future.
Brent Sobleski covers the NFL and NFL draft for Bleacher Report. Follow him on Twitter @brentsobleski.