The last walk to practice, the cleats clicking along the paved walkway from Dillon Fieldhouse to the massive concrete edifice, the echoes of 10,000 Men of Harvard circling through the cool, crisp fall air, ricocheting off the walls of the surrounding brick buildings: the Murr Center, Bright Arena, and the Gordon indoor track facility.

The last lap as seniors around Harvard Stadium, the lights dimmed to darkness, with the Crimson underclassmen taking mental notes from the end line.

And then Saturday’s finale at noon, stepping onto the shiny turf in front of a sold-out crowd of 30,000-plus at the Stadium for the 129th edition of Harvard-Yale.

“All important traditions,” John Collins emphasized earlier this week, his massive 6-foot-4-inch, 305-pound frame taking up a large chunk of a black leather couch in the coaches’ lounge inside Dillon.

The senior offensive lineman has soaked it in, grateful for what has been an opportunity of a lifetime, his dedicated, working-class parents, Walter and Jean, deeming it essential that their strapping son, with gifts on and off the field, receive the best education possible.

“I always wanted to go to Harvard, but it seemed impossible,” Collins said.

His father, a North Quincy High grad who owns three restaurants on the South Shore and sped to his fifth world title in offshore powerboat racing off West Palm Beach, Fla., in October, was an outside linebacker for Dick MacPherson at UMass in the mid-1970s.

The ticket for his son to Mather House, Academic All-District 1 honors (government major), and potentially a professional career for the product of Scituate Youth Football was the Roxbury Latin School. As a freshman, Collins lined up alongside a pair of Harvard-bound seniors, James Williams and Mike Lawler, who would become his teammates for one more season when he landed in Cambridge.

On the lacrosse field, Collins was an imposing defensive attack. On the wrestling mat, he placed third in the prep nationals at 285 pounds.

“Roxbury Latin, that’s where Harvard became a reality,” he said.

When coach Tim Murphy presented an offer to suit up for the Crimson, “I was trying to play it cool, but my mother was in tears,” said Collins, who credits Ken Conn, his revered line coach at Latin, along with former head coach Michael Turner, for instilling the fundamentals and work ethic that allowed him to develop into a fixture at guard, but with the athleticism and smarts to seamlessly shift to tackle or center.

“I know every parent says it,” said the elder Collins, as proud as a father could be, “but he is a great kid. Harvard has been absolutely fantastic for him, we could have not asked for anything more.”

Collins’s versatility has been in dire need this year, with the Crimson dealing with season-ending injuries to right tackles Will Whitman and Cole Toner, and center Jack Holuba being hobbled (although he has insisted he will play against Yale).

“He has been the glue, the one to hold it all together,” Murphy said of Collins. “The only guy that can play every position. Our most consistent lineman.”

Collins said Murphy “really preaches the whole idea of overcoming adversity and embracing the opportunity. As much as we hate to see our friends go down, it is a chance for younger guys to step up.

“Obviously, continuity is important and nice. But it’s like a luxury. Last year was very rare [Whitman, for instance, took every snap at tackle as a freshman]. I think that this is more emblematic of what an offensive line goes through. We’ll put our best five out there, and we’ll do all right. It’s all about toughness.”

Collins considers Holuba a “great player,” but he has complete faith in junior Dave Leopard at center, and Parker Sebastian at right tackle.

“It may not be pretty, but we’ll get it done,” he said.

Harvard (7-2, 4-2 Ivy League) has taken a “back-to-basics” approach in practice this week after a Crimson attack that had been humming along at 40-plus points per game was corralled at Penn in a 30-21 loss, the first game since the opener against San Diego that the Colton Chapple-directed offense failed to score 30 points.

Yale (2-7, 1-5) has dealt with its share of injury issues, primarily at quarterback, where five players have taken snaps. Former receiver Henry Furman made his first start last week against Princeton and senior linebacker Scott Williams is listed second on the depth chart.