After only one season as a defensive coordinator in the league, Dennis Allen has been hired as an NFL head coach, leaving the Broncos to go to the division-rival Raiders. The quick climb up the ladder is impressive, and by all accounts, Allen deserves the job he has been given. He played a key role in Denver's improvement from last place in the AFC West in 2010 to first place and a playoff berth in 2011 to a playoff team. The Broncos' "D" improved from 32nd in the league in 2010 to 20th last season.

However, running the Raiders will be a completely different type of challenge, one that has proven to give mixed results to coaches of Allen's age in the Bay Area.

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At age 39, Allen will be the youngest head coach in the NFL by the matter of a few months — the Steelers' Mike Tomlin turns 40 in late March, Allen doesn't turn 40 until September. He has spent the past decade in the league in some capacity, starting as a quality-control coach with the Falcons, moving to assistant defensive line and then secondary coach with the Saints before becoming the Broncos' defensive coordinator last January.

The route Allen has traveled is very similar to a former Raiders head coach — Jon Gruden. Though he had been an offensive coordinator for three seasons, Gruden was still green when he took the Raiders' head-coaching job at age 34 prior to the 1998 season. Former Oakland owner Al Davis liked Gruden's charisma and football-centric thinking, and despite having been in the NFL for only eight seasons, Gruden was given the keys to the Raiders' car.

The decision paid off. In four seasons in Oakland, Gruden won nearly 60 percent of his regular-season games and took the team deep in the playoffs twice. He eventually won the Super Bowl with the Bucs — beating the Raiders' team he had helped build.

Five seasons after Gruden left, another coach came to Oakland. Lane Kiffin was even younger when he was hired by Davis, only 31, making him the youngest head coach in league history. Kiffin had spent one season in the NFL — as an offensive quality-control coach for the Jaguars — before spending five years at USC as an offensive coordinator. His father, Monte, had helped Gruden win a championship in Tampa Bay, and the thought was that the younger Kiffin would bring his dad's intelligence and Gruden's fire to create a new dynasty in Oakland.

The decision failed horribly. After 1½ seasons, Davis fired Kiffin. The two couldn't see eye-to-eye on who to draft, which players should be in the lineup or even how the team should prepare for games. Kiffin won only five of the 20 games he coached for the Silver and Black.

Allen is older than both of these former head coaches. He has spent more time in the league before being elevated to the head job. And unlike the situations that both Gruden and Kiffin were in, Davis isn't responsible for the hiring. New GM Reggie McKenzie, who was hired on Jan. 6, made the call to bring in the franchise's first defensive-minded coach since John Madden — who, by the way, was only 32 when he was hired by the Raiders in 1969 — retired in 1978.

Only time well tell if Allen is successful as the Raiders' head coach. Being young has proven to be both successful and detrimental to head coaches for the franchise in the past. Allen will create his own path, walking side-by-side with McKenzie, and not be judged against the other young coaches because of age. He'll be judged by wins, the main reason the team hopes it has found the next Gruden, not the second coming of Kiffin.

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