In the early stages of an ambitious rebuild, Washington Football Team Coach Ron Rivera often used the Buffalo Bills as a template. He consulted Bills General Manager Brandon Beane and Coach Sean McDermott, former colleagues with the Carolina Panthers, as he assembled the bedrock of his roster.

Even though Rivera said those complementary pieces are “falling into place nicely” and even though he will use Sunday at Buffalo as a “measuring stick” for his team’s progress, the game also will remind Rivera of the biggest hurdle he has left: finding a franchise quarterback.

This matchup — Josh Allen vs. Taylor Heinicke — is as good a distillation as any of where Washington is and where it wants to be. Heinicke is Washington’s ninth starting quarterback since 2018, while Allen, who was drafted with the seventh overall pick that year, has developed from a raw, big-armed prospect into a second-team all-pro — a quarterback capable of carrying a team to a conference championship game as he did last season.

Buffalo’s development of Allen, whose statistical leap from Year 2 to Year 3 was almost unprecedented, is critical to the Bills model Rivera has drawn from. And while it’s also one of the hardest parts to replicate, Rivera said he delayed investing in a young quarterback to shore up the rest of the roster as the Bills did before picking Allen in Year 2. (Washington was outbid for Matthew Stafford by the Los Angeles Rams in trade discussions this offseason and out of range for the top quarterback prospects in the draft.)

If Washington goes all-in on a rookie after this season, McDermott stressed the importance of making everything work in concert.

“It is a comprehensive plan that you put on the table when you draft a young quarterback,” the Bills coach said Tuesday. “Josh, to his credit, has taken … a lot of ownership of that process. You have to have that as well.”

In Carolina, Rivera began his tenure with a rookie franchise quarterback after the Panthers drafted Cam Newton in his first season. But Rivera noted the origins of an adaptive, quarterback-second rebuilding model go back to Coach Bill Walsh, the architect of the West Coast offense and the three-time champion San Francisco 49ers in the 1980s. Rivera, down branch on the Walsh coaching tree, pointed out the Bills have been “very methodical” in acquiring players and limiting staff turnover.

“It’s been a proven model,” Rivera said. “It's not the West Coast offense, per se, as much as it's the West Coast way of doing things, and that's having a plan and preparing for every situation and circumstance.”

Washington’s franchise quarterback search has been more complicated than Buffalo’s. After Dwayne Haskins, a 2019 first-round pick, flamed out last season, the team signed Ryan Fitzpatrick as a veteran stopgap. After Fitzpatrick suffered a hip injury in the second quarter of the season opener, it turned to Heinicke, a 28-year-old journeyman who has shown promise in his 11 quarters of play in Washington but has seemed a long shot to assume the franchise quarterback mantle.

On Sunday, Heinicke will face the first defense to prepare solely for him over the course of a full week since December 2018. Buffalo, an experienced unit, promises to be a difficult challenge coming off a shutout of the Miami Dolphins. If Heinicke can continue playing at a high level — he finished 34 for 46 for 336 yards with two touchdowns and an interception against the New York Giants — and sustain it against an upcoming gauntlet that includes several games against elite quarterbacks, he could state a case to be the long-term solution.

The irony of Heinicke-Allen is that, in some ways, their backgrounds are similar. Both arrived in the NFL from outside the football factories of the Power Five college conferences and like to extend plays with their legs, using speed and athleticism to create off script. But Heinicke, a 6-foot-1 undrafted free agent in 2015, is also quick to note the physical attributes that separated them as prospects.

“He’s five inches taller than me, and he has a rocket arm,” Heinicke said. “But I see some similarities in the way that if something breaks down, he can kind of make something happen. He’s a fun quarterback to watch.”

Heinicke has made up for physical limitations with head and heart. He has delivered most passes on time and on target, and his resiliency and poise has turned teammates into supporters. Offensive coordinator Scott Turner, who has championed Heinicke throughout his career, believes Heinicke’s level of play is sustainable.

“There’s going to be up and downs … but he’s got the skill set to continue to be successful,” he said.

If he is, Washington might have found a rare answer at the game’s most challenging position. If he’s not, the franchise will find itself in a familiar position, attempting to find the next version of the quarterback it will be trying to stop on Sunday.