MINNEAPOLIS — Minnesota Vikings defensive end Everson Griffen has been sidelined indefinitely by an undisclosed situation that has caused concern within the organization about his well-being.

Griffen was ruled out on the pregame injury report against Buffalo on Sunday because of knee trouble. When asked afterward why Griffen wasn't on the sideline, coach Mike Zimmer said the ninth-year player and three-time Pro Bowl pick was dealing with a "personal matter."

KSTP-TV reported on Monday night, citing unnamed sources, that Griffen was involved in a disturbance at a downtown hotel on Saturday afternoon. He was not arrested.

General manager Rick Spielman said the team was "certainly concerned" by the incident and currently focused on Griffen's well-being.