And then there was one.

The Seattle Seahawks have hired Mike Macdonald, 36, as their new head coach. He becomes the youngest coach in the league, supplanting 37-year-old Jerod Mayo of the New England Patriots, who was hired earlier this month. Macdonald also replaces Pete Carroll, 72, who had been the league's oldest coach, in the Pacific Northwest.

With Macdonald headed to Seattle, the Washington Commanders are left as the only team with a vacant HC opening.

Macdonald spent the past two years as defensive coordinator for the Baltimore Ravens. For the last 10 seasons, he's been working for the Harbaughs – nine years on Baltimore's staff in various defensive capacities for head coach John Harbaugh but one season (2021) as defensive coordinator for Jim Harbaugh's University of Michigan Wolverines.

Renowned as a bright teacher with great enthusiasm for the game and its players, Macdonald's profile has been steadily on the rise in recent years. The AFC North champion Ravens surrendered the fewest points in the league in 2023, allowing 16.5 points per game. They also led the NFL with 60 sacks and 31 takeaways.

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Macdonald likely has a lot of work to do to bring Seattle up to that standard, though he will find talented players in the building. A perennial Super Bowl contender a decade ago with their "Legion of Boom" defense, the Seahawks have regressed greatly, last fielding a top-20 D in 2018. The falloff coincided with ownership's decision to move Carroll into an advisory position after a 14-year run that included two Super Bowl appearances. Carroll and Co. captured the organization's only Lombardi Trophy to cap the 2013 campaign.

Macdonald will inherit a team that also has to decide how long to stick with veteran quarterback Geno Smith, 33, who's under contract for two more seasons. The Seahawks are young and deep at running back. The wideout trio is also strong, though Tyler Lockett, 31, has a nearly $28 million cap hit in 2024, so it's worth wondering if he'll be staying. The offensive line remains suspect but has youthful potential. Defensively, Seattle has a solid group of corners, however Riq Woolen often came off the field – and not for health-related reasons. Linebackers Jordyn Brooks and Bobby Wagner, still among the league's elite at 33, are headed for free agency as is D-lineman Leonard Williams. Safety Jamal Adams is a liability in coverage and contractually, hence virtually untradeable.

Plenty of potential here, but a lot of work to do – especially in a division run by the NFC champion San Francisco 49ers and with the Los Angeles Rams seemingly rising anew.

Follow USA TODAY Sports' Nate Davis on X, formerly Twitter @ByNateDavis.