Gary Kubiak Reportedly Retiring from NFL

Denver Broncos head coach Gary Kubiak reportedly told the team he is retiring, per Ian Rapoport of NFL Network

ESPN.com's Adam Schefter initially reported Kubiak was planning to step down, citing health concerns. 

"You guys know, I love this league, I love the Broncos, I love the work," Kubiak told reporters. "I'm all-in on the Raiders right now. There will be time for reflection and all that stuff next week, but right now it's time to focus on what we're doing."

Kubiak was forced to miss a game against the San Diego Chargers in October with a "complex migraine condition." He previously suffered a ministroke in 2013 when coaching the Houston Texans; he was fired with three games remaining in that season.

Kubiak then spent one year as the Baltimore Ravens offensive coordinator before taking over in Denver. The Broncos won their third Super Bowl championship under Kubiak's leadership in 2015 but are a disappointing 8-7 this season.

Mike Klis of 9News reported several Broncos offensive assistants were expected to be replaced before news of Kubiak's pending resignation broke. Denver ranks 22nd in scoring offense, 20th in passing and 28th in rushing. While an all-time great defense propped up a mediocre Broncos offense a year ago, a slight regression on that side has kept the team out of the playoffs.

The Broncos could be in store for wholesale changes, particularly on the offensive side. Trevor Siemian hasn't been the answer at quarterback, but 2016 first-round pick Paxton Lynch has looked like a project in his own right in limited action. It's possible Denver's next coaching staff will look to install a quarterback of its own choosing.

The Broncos have also gotten limited production from rookie running back Devontae Booker, though that's partially because Denver opponents do not fear the passing game.

Kubiak has gone 81-75 across 10 seasons as an NFL head coach heading into Sunday. 

Follow Tyler Conway (@jtylerconway) on Twitter.