The Buffalo Bills fired head coach Sean McDermott at the conclusion of the 2025 NFL season. Perhaps that’s something you heard. We may have even discussed it a bit here at Buffalo Rumblings. With McDermott’s firing came changes, not least of which involve the defense.
Gone is McDermott’s nickel-base, even-front defense. In is defensive coordinator Jim Leonhard’s odd-front defense that, while a 3-4 in name, seems to be something that will look like a hybrid or multiple front in practice. Truthfully,
we have no idea what the new defense will look like, and we won’t until Week One of the 2026 NFL season. What we do know is that it’s going to be something entirely different from the scheme we’ve watched for the last nine seasons.
In today’s edition of “91 players in 91 days,” we discuss an undrafted rookie inside linebacker. Might the shift in scheme leave the door open for some young blood at a position clearly in transition after the scheme change?
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Name: Theron Gaines
Number: 54
Position: ILB
Height/Weight: 6’1” 237 lbs.
Age: 21 (22 on 6/9/2026)
Experience/Draft: R; signed with Buffalo following the 2026 NFL Draft
College: Tennessee Tech
Acquired: UDFA signing
Financial situation (per Spotrac): Gaines signed a three-year contract worth $3.12 million overall. Of that total, $20,000 is guaranteed. That figure is what the Bills will carry in the form of a dead cap number if Gaines is released. If he makes the 53-man roster, he carries a cap hit of $891,666 for the season.
2025 Recap: After being named Second-Team All-Conference as a defensive lineman during his junior year, Gaines moved to linebacker and capped off his college career with a stellar senior season. He totaled 92 tackles, including 14.5 tackles for loss, in 13 games. He notched 6.5 sacks, as well. All of those totals were career-highs. Gaines also forced a fumble, recovered three fumbles, and returned his lone interception for a 60-yard gain. He had two pass breakups, as well. He had experience at both inside and outside linebacker, and according to an interview with NFL Draft Diamonds, his preference was to play in a 4-3 defense since they could “do so much more” with an extra linebacker on the field. He was a finalist for the Buck Buchanan Award, which is given annually to the nation’s top defensive player in the FCS Division.
Positional outlook: Gaines is one of seven players listed at inside linebacker on the current roster. The others are Joe Andreessen, Terrel Bernard, Demetrius Flannigan-Fowles, Jimmy Ciarlo, Dorian Williams, and Keonta Jenkins. An eighth linebacker, fourth-round draft choice Kaleb Elams-Orr, is merely listed at “LB,” though he’s likely to play as an inside linebacker in Buffalo’s new 3-4 defense.
2026 Offseason: Gaines has attended rookie minicamp and all other OTAs thus far.
2026 Season outlook: For my money, the position on this roster with the most question-marks is inside linebacker. If you want a hot take, I think it’s the weakest position on the team; if you want me to keep it mild, it’s just the grouping that has the least clarity given the new defensive front. Many of the players listed here are undersized by NFL standards, and most of them have little to no experience playing in a 3-4 front. Granted, the Bills are likely to be quite multiple in their defense, and they aren’t going to play a traditional 3-4 like the 1990s Bills did. Regardless, this group is still the one that gives me the most pause in evaluating the 2026 Bills.
This is a long-winded way of saying that, if there is a position on the roster where an undrafted free agent could come in and surprise, it’s the inside linebacker spot. Gaines might be a converted defensive lineman with limited experience as a linebacker, and he might have only played linebacker in a 4-3 front (or a 4-2-5) in college, but that lack of 3-4 experience doesn’t necessarily put him behind the proverbial eight-ball here. What he does have is the size to withstand playing in the middle of an odd-front defense, and that’s before spending a year in a professional strength and conditioning program.
At Vanderbilt’s pro day, Gaines showed off some solid athleticism in the spring. He put up 20 reps of the 225-pound bench press, leapt 37” in the vertical jump and 9’11” in the broad jump, and ran the 40-yard dash in 4.63 seconds. He struggled in the short-area drills, logging a 4.55-second time in the 20-yard shuttle run and a 7.5-second time in the three-cone drill, but overall, his measurables are noteworthy.
If we assume that Andreessen, Bernard, Williams, and Elams-Orr are solidly on the roster, it’s not entirely crazy to think that Gaines has a chance at cracking the 53 as a special teams player-slash-fifth linebacker. It’s much more likely that he’s fighting for a spot on the practice squad, but it could come down to a numbers game. Either way, Theron (pronounced THEE-ron) Gaines is going to be a player to watch this summer.
