HENDERSON, Nev. -- Las Vegas Raiders president Marc Badain, who began his tenure with the team as a training camp intern in 1991 and served a central role in the team's move from Oakland to Southern Nevada last year, resigned on Monday.

The move was met with shock in the organization, while Badain, 51, simply said it was time for him to "focus on my family and look ahead to new pursuits" while thanking owner Mark Davis.

"The successful construction and operation of Allegiant Stadium has been unequivocally the most challenging part of my 30 years with the organization," Badain said in a text. "Seeing it through to the end has been rewarding beyond measure. Together the Raiders and Las Vegas accomplished what seemed impossible.

"I am forever grateful to MD for his unwavering support and friendship. I wish him and the Raider family the best. I will always feel a part of the team because everyone knows...Once A Raider Always A Raider."

Davis, meanwhile, said Badain was "an integral part of the Raider Family" in a team release while wishing him the "Best in Whatever The Future Holds."

Dan Ventrelle, the team's executive vice president and general counsel, will assume the role of team president.

Badain had an in with the Raiders as his grandfather, Al Badain, was Al Davis' basketball coach at Brooklyn's Erasmus Hall High School. The younger Badain became a full-time administrative assistant to Art Shell's coaching staff in 1992 before he moved to the finance department in 1995, where he helped create a depth chart for the Raiders based on the salary cap. Badain became CFO in 2004 before becoming interim president in 2013, following Amy Trask's resignation, and had the interim tag removed in 2015.

In the upcoming book "If These Walls Could Talk: Stories from the Raiders Sideline, Locker Room and Press Box," Badain said he grew up a Raiders fan "because of a family connection."

"So then I had the benefit of getting a job here," he said. "And so when you have that sort of built up in your mind -- what it's going to mean to work there -- and then you come there and you see it in reality, and you see what it's like and you see that family atmosphere and a little bit of the dysfunction, which I don't say it in a negative way, I mean it from the personality of the place when I got there 30 years ago and some of that still exists here. I think that that's important."

The Raiders, who went 8-8 last season to finish in second place in the AFC West behind the Kansas City Chiefs, are about to enter their second season in Las Vegas.

Paul Gutierrez is the co-author of the upcoming book "If These Walls Could Talk: Stories from the Raiders Sideline, Locker Room and Press Box."