The debut of the brand-new Buffalo Bills is fast approaching on Saturday afternoon. The Bills will unveil a new head coach, a new defense, a new defensive coordinator and a $2 billion new stadium in a game setting when they take on the Carolina Panthers at Highmark Stadium.However, since head coach Joe Brady has been in Buffalo before, and the stadium got its curtain-opening night for the Return of the Blue & Red practice last weekend, the new-look defense might be the most intriguing part of the game. Defensive coordinator Jim Leonhard has put together plenty of different looks for the Bills’ new 3-4 defense through two weeks of training camp.The Bills have been mixing and matching across all three levels of the defense to see what sticks. But on Saturday, Leonhard and the fanbase will finally get to see it live against someone other than their teammates.“Anytime you get against different competition, things change,” Leonhard said Tuesday. “I am excited just to continue to push. We’ve only had so many days in pads, right? We’ve only had so many days where extended physical, you know, stress on these guys — whether it’s the play number or just the physicality of it. We’re going to continue to grow through this preseason.”Is winning the Super Bowl a fairytale for the Buffalo Bills?Robert MaysWhen asked about the idea of healthy defensive starters playing, Leonhard didn’t come right out and say it was happening, but he did push it in that direction.“I think the plan is for guys to play and get a taste of the scheme live. Let’s go finish,” the defensive coordinator said. “As far as I’m concerned, guys are going to go play, to be determined a little bit on how much, but it’s going to be exciting for guys to get out there and just kind of let it rip.”As the Bills get closer to that first taste of game action in a new defense, their players went through their first pair of practices at Orchard Park.Here’s what stood out.Positive T.J. Sanders developmentsWhile plenty of defensive players have been getting the attention this summer through the new scheme, one relatively high-draft investment has slipped through the cracks a bit. Second-year defensive lineman T.J. Sanders has a potentially big role on the way despite limited action as a rookie, and the question is how he’ll respond to that enhanced opportunity. When asked about what they’ve seen and what they’d like to see more of, Leonhard was quick to point out how much they’ve put on Sanders’ plate.“We’re asking him to play multiple roles,” Leonhard said. “We’re not just limiting him to one spot. So he’s moving to different areas of that defensive line, whether it’s our base package and our nickel package. So he is probably one of the guys who’s done the most and playing at a high level.”Some of Sanders’ experience during his rookie season likely contributed to that versatility, as he played inside at defensive tackle and outside at defensive end when the Bills were dealing with numerous injuries in 2025. It’s unlikely that Sanders, at his weight (297 pounds), will play much nose tackle for the Bills, but lining up both on the inside shoulder of the offensive tackle and on the outside on other snaps gives him some different avenues to help bring him along as a pass rusher in game settings, which is what the Bills drafted him to do in the first place.Leonhard also said Sanders has had to undergo the challenge of getting moved around more than his other defensive line teammates, so from a volume standpoint, he hasn’t had quite as many reps in one spot as some others. But more encouragingly, Leonhard also brought up the part of Sanders’ game that needed refinement.“The physicality is improving,” Leonhard said. “What I’m seeing, like, he is committed to trying to be the physical player when he needs to be. Everybody knows he has some pass-rush ability and ability to get to the quarterback. And he’s flashed both. And again, now it’s just creating consistency.”On the Bills’ first unofficial depth chart of the summer, Sanders was listed as one of their three starting defensive linemen in base formation. That is mostly consistent with how things have gone through camp and Sanders getting first-team time, so it seems as though the Bills are hoping for a big jump in Year 2 from their 2025 second-round pick.Hairston ramps upThe Bills have been without presumed starting No. 2 cornerback Maxwell Hairston for several practices, as he has missed time with an undisclosed injury. Throughout his time away, Hairston has been extremely visible during practices, often jogging up to celebrate with his cornerback teammates whenever they made a play against the opposition. That gave the sense that whatever he had been dealing with was never really a long-term concern. Those sentiments were backed up on Tuesday by Hairston being the first of the currently injured players to begin ramping up during practice.After the Bills went into positional drills, Hairston emerged and went over to the side with some members of the strength and conditioning staff to begin some movement drills. Hairston was dressed in helmet and jersey, which is as good a sign as any.