ORCHARD PARK, N.Y. -- The first thing you notice is their sheer mass. The hulking dude in the red No. 17 jersey hovering above almost everyone else in the offensive huddle. And then, across the practice field, the specimen wearing No. 49 in white, the quarterback of the defensive huddle, who seems to be from a different gene pool at times, a teenager sticking out among the grown men.

The future of the Buffalo Bills -- one agonizingly sculpted out of a series of trades and transactions dating back to last summer -- rests quite prominently on these two sets of shoulders. One belonging to Josh Allen, the quarterback who the Bills moved up to seventh overall to select a few weeks back. The other belongs to Tremaine Edmunds, the wunderkind linebacker who just turned 20 whom the Bills moved up to 16th overall to select. Both are raw, physically imposing prospects whose development will define the bold and ambitious regime of coach Sean McDermott and general manager Brandon Beane.

If both become anything close to what this franchise believes they can mold into, then the Bills just might be best positioned to become the beasts of the AFC East once the Patriots' death grip on the division inevitably wanes with even Tom Brady unable to play like an MVP forever. For now, they seem to be operating at different ends of the growth scale, with Allen taking his lumps and trying to hone his accuracy with the third-team offense during the team's second week of organized team activities, while Edmunds gets thrust into the choppy waters serving as the middle linebacker in McDermott's probing scheme, serving as essentially the central nervous system for the starting defense.

"You see obviously their physical size; they are both big for their positions," Beane said during a long chat detailing the long path the Bills took to land these two first-round picks. "They are great young men. They have come in here and we've got a quarterback in Josh, but we also got kind of the quarterback of the defense in Tremaine, and he's playing the Mike linebacker for us. And it's like anything, it's fast and furious, but he's jumped in there and he's not acting like it's too big. He's learning on the fly.

"Both of these guys are coming in and they are bowing to the veterans, but they are both showing confidence, too, which is what you want. They both understand that they have to earn their stripes, so they're not the loudest ones in the room. But when it's their turn they are getting up and making plays, and that's all you can do right now in shorts and t-shirts."

Edmunds, of course, seems destined to start from Day 1. Being the QB of the 'D' ain't easy, but it pales in comparison to all that comes with being a rookie starting QB in this league. His athleticism is off the charts and moving to middle linebacker should allow him even more room to roam and run and wreak havoc compared to how he was often deployed at Virginia Tech. His NFL bloodlines with his father and brothers are deep and unique and his 6-foot-5 frame and ridiculous wingspan make him seem like an eagle lurking above the rest of the field at times (particularly when serving as the "center fielder" among the three deep defenders in the prevent defense at practice). It's hard to envision a scenario where Edmunds is not on the field virtually all the time as the Bills try to add bite and play-makers to what was the league's 26th ranked defense in 2017 (29th against the rush and 20th against the pass).

"Tremaine has done a really good job up to this point," said defensive coordinator Leslie Frazier, who praised Edmunds at length for finding a way to quickly meld into this veteran group. "It's a challenge coming in as a rookie for sure, and then being the middle linebacker, to lead; you are in a leadership role and being asked to call the defense and set the front and doing a lot of things that are required to lead the entire group. And that's asking a lot of a rookie. But up to this point he's handled it extremely well, and we don't see any indication that he won't continue ... so we'll just keep putting a bit more on his plate as he goes."

It's certainly an adjustment for Edmunds, but one he is clearly taking in stride.

"Just learning everything," Edmunds said when asked about his biggest challenge thus far. "This is professional, this is the big leagues, now. Everybody is going to be fast, and everybody is going to be pretty much built like I am [Editor's note: No they aren't!], and the kind of athlete that I am, so you have to make sure you have everything down 100 percent, because things are going to start moving fast. That's the biggest adjustment right now."

Of course, the far more intriguing and complex question involves when Allen takes the field in a regular season game. For as great as Edmunds may be -- in the short and long term -- the Bills parted with veterans like Ronald Darby and Sammie Watkins and Marcell Dareus and Cordy Glenn and some picks along the way to get in a position to land a franchise quarterback in the 2018 draft. Everything Allen does will be under scrutiny and the hopes of a franchise without a playoff win for decades will live and die with him.

He's starting at the bottom, watching projected starter AJ McCarron and 2017 backup Nathan Peterman work in team drills before Allen's group takes the field. He spent downtime during practice going over spin moves to escape the rush and footwork with Peterman in particular and, when doing drills against air (no defenders) generally worked directly alongside McCarron which will allow coaches to easily compare their mechanics in tape review.

Allen was hardly perfect in Thursday's session, and his accuracy will remain the most discussed and dissected part of his game. Several balls skidded low and in the grass during the 11-on-11 drills -- Allen made a point to come over to veteran Rod Streater and pat him on the back after one series of plays in which the quarterback's play was shaky. There were a lot of short passes and screens -- not too much to show off Allen's powerful arm -but when the rookie took off with the ball his natural speed and athleticism were apparent.

"Day by day we get better," Allen said. "And obviously some more stuff goes in [to install the offense] every day, but just being able to retain it and go out on the field and execute the play hasn't been too bad so far. Coach [Brian] Daboll has been doing a really good job of interpreting and explaining the play, and when we get on the field I just try to remember the things he's told us and taught us, and just go out and execute."

Daboll, a coordinator who several teams coveted after successful stints in college and the pros, is putting in an entirely new offense from a year ago, so even Peterman, the only holdover quarterback, isn't at much of an advantage. The group of receivers is greatly changed and the offensive line has been overhauled, with veteran stalwarts Richie Incognito, Eric Wood and Glenn all gone. It's essentially starting from scratch.

"It's very creative," left tackle Dion Dawkins said. "Nothing is easy. It's going to take a lot of time to get it down."

At the same time Daboll is trying to cultivate Allen and get him up to speed as quickly as possible, while McCarron and Peterman are also very short on real game NFL reps themselves. Sounds like a fairly daunting task, and one that could leave the Bills in transition and experiencing some growing pains this year.

"We're still getting a feel for our personnel," Daboll said.

Then again, none of this was constructed with September 2018 in mind. The arduous overhaul of a long stilted and sated roster won't always be smooth, and there will be rough patches for Edmunds and the Bills, and especially for Allen, too, whenever he does surpass McCarron atop the quarterback depth chart. The rookie won't be making any proclamations about when that day might come, and seems to grasp the magnitude of the chore ahead.

"They've obviously put a lot of trust in me and what I can do, and what I am hopefully going to do," said Allen, who said his focus isn't on Week 1 but rather being the best he can be. "But in the meantime, I'm learning. I'm learning from AJ and Nate and trying to be the best teammate I can be in everything and trying to learn how to be a pro. We're looking for long-term success down the road, and that starts now."