Another branch off the Bill Belichick coaching tree has officially been chopped down.
After a 2–8 start to the 2025 season, the Giants fired coach Brian Daboll on Monday morning, mere hours after his team blew its fourth double-digit lead—and third in the fourth quarter—this year. His tenure in New York ends with a 21–41–1 record, highlighted by a postseason appearance in 2022 but ultimately defined by his team’s inability to close things out in tight games (and his front office’s decision to let running back Saquon Barkley walk in free agency, a discussion for another day).
Daboll is the second coach to be fired this season and, as mentioned above, joins a laundry list of those who’ve failed to find NFL head coaching success from the Bill Belichick tree. The 50-year-old began his NFL career as a defensive assistant with the Patriots in 2000—poached from a stint under Belichick’s close friend Nick Saban at Michigan State—and spent a total of 11 seasons in New England from ‘0 to ‘06 and again from ‘13 to ‘16. Daboll has also held assistant roles with the Jets ('07 to '08), Browns ('09 to '10), Dolphins ('11), Chiefs ('12), Alabama ('17), and Bills ('18 to '21).
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While Belichick is widely regarded as one of the greatest coaches in NFL history, his assistants have failed to replicate his Super Bowl-winning success—and Daboll is far from the only example. Here's a look at how the rest of the 73-year-olds' coaching tree has fared once they decided to branch out on their own.
Romeo Crennel
Romeo Crennel
Crennel coached both the Cleveland Browns and the Kansas City Chiefs. / Ron Chenoy-Imagn Images
Head coach jobs: Browns (2005 to '08), Chiefs ('12)
Head coaching record: 32–63 (.337)
Current job: Retired
Long a respected defensive mind, Romeo Crennel first overlapped with Belichick during their time together with the Giants in the early 1980s, coaching under Bill Parcells. He then became a key cog in the Patriots’ early dynasty success, serving as the team’s defensive coordinator from 2001 to ‘04 and winning three Super Bowls with the club.
Following New England’s Super Bowl XXXIX win over the Eagles, Crennel was hired as the Browns’ head coach in February of 2005. He spent four seasons in Cleveland, amassed just a 24–40 record, and was fired after the 2007-08 season.
Crennel later returned to the NFL as a defensive coordinator with the Chiefs and, in mid-2011, was named interim head coach following the firing of Todd Haley. He was then given a real chance, hired by Kansas City as its full-time head coach the following season, but was fired after a 2–14 campaign in 2012.
Eric Mangini
Eric Mangini
Mangini left the Patriots to coach the Jets in 2009. / Kirby Lee-Imagn Images
Head coach jobs: Jets (2006 to '08), Browns ('09 to '12)
Head coaching record: 33–48 (.407)
Current job: Fox Sports analyst
Eric Mangini began his coaching career under Belichick, serving as an offensive assistant with the Browns in 1995. Notably an alumnus of Belichick's Wesleyan University, Mangini was brought up the ranks by the now-UNC coach, working with him during his time with the Jets ('97 to '99), and of course the Patriots ('00 to '05).
After a successful season as New England's defensive coordinator in '05, Mangini was hired as the Jets' head coach in '06. That move ultimately strained his relationship with Belichick, which further worsened when he allegedly exposed the Patriots' habit of using press box cameras to videotape opponents' sidelines—an incident eventually known as "SpyGate." The two have never fully reconciled. In fact, during a '16 press conference, Belichick seemed to deliberately omit Mangini when listing off a slew of coordinators that had worked under him in New England.
Mangini was fired by New York in ‘08 and hired by the Browns during the following coaching cycle in ‘09. He ultimately never found success as a head coach, and was fired by Cleveland after two back-to-back 5–11 seasons.
Josh McDaniels
Josh McDaniels.
Josh McDaniels has had two stints as a head coach in the NFL. / Ron Chenoy-Imagn Images
Head coach jobs: Broncos (2009 to '10), Raiders ('22 to '23)
Head coaching record: 20–33 (.337)
Current job: Patriots offensive coordinator
The gift that keeps on giving, Josh McDaniels is now into his third(!) stint as the Patriots’ offensive coordinator.
Like Daboll, McDaniels was poached from Nick Saban’s Michigan State staff in 2000 and brought up through the New England ranks under Belichick. He first served as the team’s play caller in ‘05, was promoted to OC in ‘06, and after two successful seasons that included an undefeated '07 campaign, was hired as the Broncos' head coach in '09—replacing Mike Shanahan.
McDaniels’s tenure in Denver came with plenty of controversy, including the trade of Jay Cutler, the drafting of Tim Tebow, and a fine for taping a 49ers walkthrough practice. He was ultimately fired by the team following a 3–9 start to his second season.
Thirteen years later, McDaniels was given another chance to lead an NFL franchise when he was hired as the Raiders’ head coach in 2022. Unfortunately, the stint didn't go well either, and he was again fired midway through his second season.
Add his spurning of the Colts job in 2018, and the verdict is simple: Bad head coach, great OC—as evidenced by Patriots quarterback Drake Maye’s MVP start to the 2025 season.
Bill O’Brien
Bill O’Brien
Bill O’Brien is the lone coach from the Belichick tree with a winning record. / Tim Warner/Getty Images
Head coach jobs: Texans (2014 to '20)
Head coaching record: 52–48 (.520)
Current job: Boston College head coach
The lone branch of the Belichick tree to boast a winning record as an NFL head coach, Bill O’Brien began his professional football career as an offensive assistant with the Patriots in 2007. He took over for Josh McDaniels as play caller in ‘09, was promoted to offensive coordinator in ‘11, and ultimately got his first head coaching job in the college ranks with Penn State in ‘12.
After two successful seasons in Happy Valley, O’Brien was hired as the Texans’ head coach in 2014. He spent just over six seasons in Houston and complied a 52–48 record, but after being handed the reins to the personnel department in ‘20, things unraveled quickly and he was fired after a 0–4 start to the season.
O’Brien since returned to the Patriots in 2023, and currently serves as the head coach at Boston College.
Matt Patricia
Matt Patricia
Matt Patricia spent just over two seasons as the Lions' head coach. / Junfu Han / USA TODAY NETWORK via Imagn Images
Head coach jobs: Lions (2018 to '20)
Head coaching record: 13–29–1 (.302)
Current job: Ohio State defensive coordinator
Matt Patricia began his NFL coaching career with the Patriots in 2004. He served as an assistant offensive line coach before moving over to the defensive side of the ball in '06 and working his way up to defensive coordinator by '12.
The long-haired, backwards-hatted, pencil-behind-the-ear rocket scientist was hired by the Lions as their head coach in 2018. He spent just over two seasons in Detroit and was fired after a 4–7 start to his third campaign.
Patricia returned to New England as an assistant from 2021 to '22. He currently serves as Ohio State’s defensive coordinator, where he’s been able to find success calling the Buckeyes’ defense in '25.
Brian Flores
Brian Flores
Brian Flores was fired by the Dolphins after three seasons. / Sam Navarro-Imagn Images
Head coach jobs: Dolphins (2019 to '21)
Head coaching record: 24–25 (.490)
Current job: Vikings defensive coordinator
Much like the rest of the bunch, Brian Flores was given his first chance by Belichick and the Patriots. After four seasons as a scout, he was named a special teams assistant in 2008 before joining the defensive staff in ‘12.
Flores served as New England’s linebackers coach from 2016 to ‘18 and took over defensive play-calling duties in his final season after Patricia left for the Lions.
He was ultimately hired as the Dolphins’ head coach in ‘19 and spent three seasons in Miami before being fired following a 9–8 finish to ‘21. His tenure in South Beach ended with a poor relationship with Tua Tagovailoa, reports that he was asked to tank by owner Stephen Ross, and a class-action lawsuit against the NFL alleging racial discrimination.
Flores currently serves as the Vikings’ defensive coordinator and is regarded as one of the league’s top defensive minds.
Joe Judge
Joe Judge.
Joe Judge spent two seasons as the Giants' head coach before returning to New England. / Danielle Parhizkaran/NorthJersey.com / USA TODAY NETWORK
Head coach jobs: Giants (2020 to '21)
Head coaching record: 10–23 (.303)
Current job: Ole Miss quarterbacks coach
Joe Judge was brought to Belichick’s Patriots after working as a special teams assistant at Alabama under Nick Saban at Alabama from 2009 to ‘11. He served in the same role in New England from ‘12 to ‘14, was promted to special teams coordinator in ‘15, and added wide receivers coach to his title in ‘19.
The following year, Judge was hired as the Giants’ head coach, replacing Pat Shurmur. He went 10–23 over two seasons and—after a controversial QB sneak on 3rd and 9, and an awkward 11-minute press conference rant—was fired.
Judge currently serves as the quarterbacks coach at Ole Miss.
Brian Daboll
Brian Daboll.
Brian Daboll's Giants blew another fourth-quarter lead before being fired on Monday. / Eric Hartline-Imagn Images
Head coach jobs: Giants (2022 to '25)
Head coaching record: 21–41–1 (.341)
Current job: Fired
While you can see above for the low-down on Daboll, it’s worth noting that he’s likely to get another shot in the NFL coaching carousel—much like the majority of Belichick disciples.
Daboll’s tenure with the Giants started hot and fizzled out, but he’s a great offensive mind. His intangibles should land him another opportunity to lead a franchise at some point in the near future.
Jerod Mayo
Jerod Mayo
Jerod Mayo was fired after just one season with the Patriots. / David Butler II-Imagn Images
Head coach jobs: Patriots (2024)
Head coaching record: 4–13 (.235)
Current job: N/A
Arguably the worst branch of the tree, Mayo was hired to replace Belichick in New England after he parted ways with the franchise in January of 2024.
Mayo was drafted by and played for the Patriots from 2008 to ‘15 before joining their coaching staff in 2019. He served as linebackers coach for five seasons and was handpicked by owner Robert Kraft to be Belichick’s successor. The timeline for his promotion was ultimately accelerated after New England’s back-to-back losing seasons in Belichick’s final years, and Mayo was handed the reins in 2024.
Following a 4–13 season that saw the Patriots regress as the year went on, Mayo was fired this past January and replaced with Mike Vrabel. He is currently out of coaching.
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