Denny Thum began his long career with the Chiefs in 1974, and it ended Tuesday evening, when the team issued a vague statement that stated neither the reason for Thum’s departure nor an explanation for the move’s unusual timing. Only that he was leaving the organization immediately.

Kansas City defeated San Diego on national television Monday night, capping a night of celebration as the Chiefs officially opened a revamped Arrowhead Stadium, gleaming with $375 million in renovations. Monday night was marketed as a turning point for the Chiefs, and Thum was seen in the stadium’s new press box showing off the view and its amenities to visitors.

Thum oversaw much of the stadium renovations and other large-scale projects, including bringing the team’s training camp to the campus of Missouri Western in St. Joseph after two decades in River Falls, Wis.

“Denny has been an integral part of the Chiefs family and this community for nearly four decades, and we thank him for his dedication and commitment to our organization,” Hunt said in the release.