ORCHARD PARK, N.Y. (AP) — First Rex Ryan, now Doug Whaley.

Bills owner Terry Pegula completed an offseason front-office purge by firing Whaley, his general manager, and the team’s entire scouting staff on Sunday, a day after completing the NFL draft.

Though pleased with the collaborative effort that took place in the draft room between Whaley and rookie coach Sean McDermott, Pegula went ahead with the change after what he called a lengthy review of his operation. Pegula said the timing coincided with the end of the draft, but he declined to detail the reasons why he felt the overhaul was necessary.

“Doug’s a good guy. He’s a smart man, but we made the decision,” Pegula said during a 15-minute news conference at the team’s headquarters. “And the reasons remain private to us.”

The shake-up further solidifies McDermott’s authority and influence, which has grown incrementally in the three months since he replaced Rex Ryan, who was fired in the final week of last season. The 42-year-old detail-oriented defensive specialist has become the voice of the franchise in discussing all team-related topics, including free agency and the draft.

Besides Whaley, the Bills also dismissed player-personnel director Jim Monos and Kelvin Fisher, the team’s former amateur scouting director who had previously been demoted to an advisory role.

Pegula said he will immediately begin a general manager search and that it was too early to speculate on candidates. He said McDermott would have some input.

One possible candidate is Carolina Panthers assistant GM Brandon Beane because of his ties to McDermott, who spent the previous six seasons as the team’s defensive coordinator.

Pegula stressed the decision to clean house was made by him and his wife, Kim.

The shake-up leaves the Bills seeking their seventh GM during what’s been a 17-year playoff drought — the longest active streak in North America’s four major professional sports. It’s the first GM search for the Pegulas, who retained Whaley when they purchased the team in October 2014.

Though Pegula backed Whaley after Ryan was fired, the owner provided few hints on why he had a sudden change of heart.

“We decided to make this change to try to get better,” Pegula said.

Whaley had three seasons left on his contract after signing a four-year extension in January 2016. After Whaley worked up the scouting ranks with the Pittsburgh Steelers, the Bills hired him as an assistant general manager in 2010. He was groomed to become the GM and took over the job in May 2013 when Buddy Nix stepped down.

In the draft, the Bills made six picks and swung several trades in addressing both immediate and long-term needs.

Buffalo opened by acquiring two selections, including a first-rounder next year, in a trade with Kansas City to move back 17 spots and select LSU cornerback Tre’Davious White at 27th.

McDermott sidestepped questions regarding Whaley’s job security, saying he was solely focused on the draft. At one point on Saturday, he credited Whaley’s work without discussing his future.

“Nothing’s changed from what I’ve said all along: Doug and his staff have done a nice job,” McDermott said. “We’ve had great conversation, to your question, the entire time in terms of healthy meetings and productive meetings.”

The Bills’ drafting history had been spotty this decade.

Of the 35 players Buffalo drafted from 2010-13, only defensive tackle Marcell Dareus and left tackle Cordy Glenn remain on the roster.

Whaley has been second-guessed on a number of selections, including the decision to trade two draft picks — including Buffalo’s 2015 first-round selection — to Cleveland to move up five spots and pick receiver Sammy Watkins with the fourth selection in the 2014 draft.

It was considered a high price to pay in a draft that produced a bounty of top-flight receivers.

Last year, the Bills selected defensive end Shaq Lawson with the 19th pick while knowing the player would likely require surgery to repair a shoulder injury that had nagged him at Clemson. Lawson aggravated the injury during the team’s rookie minicamp and eventually missed the first six games of the season.

Whaley was more successful in identifying experienced talent.

Two of Buffalo’s best additions last year were free-agent linebackers Lorenzo Alexander, who had a team-leading 12 1/2 sacks, and leading tackler Zach Brown.

Concerns were also raised regarding Whaley’s relationship with Buffalo’s two previous coaches. Doug Marrone elected to use an opt-out clause in his contract to step down as coach after the 2014 season.

In January, Pegula told The Associated Press that while it was his decision to fire Ryan, Whaley had input based on conversations he and the GM had over the season.

Whaley acknowledged he took a gamble and suggested his tenure in Buffalo might well be judged on that one move.

Both of Pegula’s Buffalo-based sports franchises are hitting the reset button. Pegula fired Sabers GM Tim Murray and coach Dan Bylsma 10 days after the NHL season ended two weeks ago.

Without going into detail, Pegula said he is close to hiring a general manager.