EAGAN, Minn. -- After refusing to receive a vaccine for COVID-19, Rick Dennison is out as a Minnesota Vikings assistant coach, sources told ESPN on Friday.

Dennison had served as the Vikings' offensive line coach/run game coordinator the past two seasons. In a statement Friday, the Vikings said they were still in discussions with Dennison about the league's COVID-19 protocols.

Another coach in the league, New England Patriots co-offensive line coach Cole Popovich, also won't be with his team in 2021 in a decision related to the COVID-19 vaccine and NFL guidelines, league sources confirmed to ESPN.

The vaccine is required for all Tier 1 staff, including coaches, front-office executives, equipment managers and scouts. Players are not required to receive the COVID-19 vaccine but will face strict protocols during training camp and throughout the season that vaccinated players will be able to forgo.

In a memo released by the league this summer, the NFL said any unvaccinated Tier 1 staff member must provide a valid religious or medical reason for not receiving the vaccine. Losing Tier 1 status prohibits coaches from being on the field and in meeting rooms and having direct interactions with players.

The Vikings noted in their statement that Dennison does not have a vaccination exemption.

Phil Rauscher has been promoted from assistant offensive line coach to fill Dennison's position, sources told ESPN. The Vikings also hired Ben Steele, who had recently been hired by Auburn as a special teams analyst, to fill the position Rauscher had held since 2019.

Dennison's departure comes at a time of transition for the Vikings' offense, which will be guided by first-year offensive coordinator Klint Kubiak. Kubiak, 34, was promoted to fill the role his father, Gary, held in Minnesota during the 2020 season.

With 27 years of NFL coaching experience, Dennison was considered a vital piece in helping bridge the gap for the younger Kubiak, given his experience calling run plays and knowledge of the scheme the Vikings have used since the 2019 season.

The Vikings were one of the league's prominent running teams in 2020 behind Dalvin Cook, who became the first Minnesota player to rush for at least 1,500 yards and 15 touchdowns in a season. Cook was responsible for 30.5% of the Vikings' scrimmage yards, the second-highest rate in the NFL behind Tennessee's Derrick Henry (33.8), according to ESPN Stats & Information data.

In New England, Popovich coached with the Patriots through the spring, and his on-field presence stood out, in part, as he was one of the only staffers to wear a mask during practice.

Popovich, who is distantly related to longtime San Antonio Spurs coach Gregg Popovich but said in September that he has never met him, was set to enter his seventh season with the Patriots. In 2020, he had shared the offensive line duties with longtime former Youngstown State offensive line coach Carmen Bricillo, who is now expected to take on more of a leading role.

The Boston Globe first reported that Popovich wouldn't be coaching with the Patriots in 2021.

Dennison, 63, worked with Gary Kubiak for more than three decades in Denver (1995-2009, 2015-16), Houston (2010-13) and Baltimore (2014). Before joining the Vikings in 2019, Dennison served as offensive line coach/run game coordinator for the New York Jets in 2018.

Rauscher is entering his seventh season as a coach in the NFL after joining the Vikings in 2020. He coached with Dennison on the Broncos staff during the 2015 and 2016 seasons and was Washington's offensive line coach in 2019.

Steele was on several NFL rosters as a tight end from 2001 to 2007, including in Houston under Gary Kubiak. He began working in the NFL in 2013 as an offensive quality control coach for the Tampa Bay Buccaneers, a position he held until 2016. Steele was later promoted to tight ends coach for the Buccaneers before moving to the Atlanta Falcons, where he was an offensive assistant in 2019 and tight ends coach in 2020. He was hired by Auburn earlier this year.

The Vikings will hold their first training camp practice Wednesday.

ESPN's Mike Reiss contributed to this report.