Minnesota Vikings offensive coordinator Norv Turner resigned on Tuesday, leaving a major void with the franchise (5-2) atop the NFC North.
The Vikings have lost two straight games and struggled offensively in those defeats.
Most observers point to an injured offensive line as the main reason for their struggles, and Turner generally has been credited with quarterback Sam Bradford's strong start to his first season with the Vikings.
Bradford was traded to the Vikings after starting QB Teddy Bridgewater suffered a season-ending knee injury in August.
"Norv Turner has resigned as Offensive Coordinator of the Minnesota Vikings," the team said in a statement Tuesday. "Pat Shurmur will assume the duties as Interim Offensive Coordinator effective immediately."
Turner added in a statement: "I have tremendous respect for Mike Zimmer, our coaching staff, and our players and at this time I think it is in the best interests of the team to step down.
"I thank the Wilf family for my time here in Minnesota and want to see our players and coaches achieve success."