The Vikings severed ties with troubled Erin Henderson on Friday, releasing the six-year veteran who had started at both the outside and middle linebacker positions.

Henderson, 27, was arrested twice on drunken driving charges in six weeks late last season. He declined to comment Friday.

Henderson started 26 games at weak-side linebacker until he moved into the starting middle linebacker spot this season. He missed a Nov. 24 game at Green Bay for "personal reasons," and Audie Cole took over as the starter. Cole was injured for the final two games, and Henderson regained his starting position. He ended up second on the Vikings in tackles, with 112.

Henderson signed a two-year, $4 million contract last March. He was due a roster bonus of $500,000 if still on the team March 20. By cutting him, the Vikings also will clear a little more than $2 million in salary cap space.

Henderson's first arrest came Nov. 19 in Eden Prairie, and 12 days later he called it "eye-opening."

"It was a wake-up call for me and, honestly, it may be something that I needed in the long run," Henderson said that day. "Something I think will help me progress and become the person I'm capable of being and the man that I want to be. It was a tough situation having to sit at home and watch your teammates and watch your guys go out there to battle."

Star Tribune, Star Tribune
Erin Henderson

He was arrested again on New Year's Day in Chanhassen.

Henderson was an undrafted free agent out of Maryland in 2008 and joined older brother E.J. Henderson with the Vikings that season. E.J. Henderson played nine seasons for the Vikings, and made a Pro Bowl as a middle linebacker, before his career ended after the 2011 season.

Will Cassel be back?

Quarterback Matt Cassel officially opted out of the final year of his two-year contract and will explore free agency. Cassel could re-sign with the Vikings, however.

Offensive coordinator Norv Turner said quarterbacks coach Scott Turner had a positive conversation with Cassel about possibly returning to the team.

"Matt is interested and he liked his experience here," Turner said Thursday. "He's excited about the things we're doing, the things we've done. I've known him for quite a while. We've talked football. I don't think I'm surprised by him opting out, if that's what he did. But I'm excited to work with Matt."