Editor's note: With Oklahoma's 2025-26 season just a few weeks away, OUInsider will examine the players who will have the biggest impact on the outcome. This article centers around senior defensive end R Mason Thomas, who is the first to be featured.

Oklahoma had a lot of priorities heading into last offseason. The Sooners made wholesale changes to the athletic department, establishing a bonafide front office led by general manager Jim Nagy. Brent Venables made several crucial hires to the coaching staff. The program attacked the transfer portal as it looked to remake the roster.

However, retaining R Mason Thomas was arguably the biggest move of the offseason.

One of the Sooners' biggest priorities was keeping the senior defensive end, and for good reason. After dealing with injuries through his first two seasons, Thomas was everything the Sooners hoped he'd be in 2024. He led the Sooners in sacks and tackles for loss, landing a spot on the All-SEC Second Team. He was the explosive and disruptive point of attack for an Oklahoma defense that finished as one of the best units in the country despite the team's disappointing 6-7 record.

But the biggest thing was his consistency. He played in every single game and started 10 of them. He logged 529 snaps, per Pro Football Focus — the fourth most on the team and more than he played in his first two seasons combined (406).

Thomas had several things he wanted to work on this offseason, including his weight.

"I wanted to focus on my run game, so with that I needed to add weight, power, lean muscles," Thomas said back in Match. "So I got with the nutrition and strength staff to get me right. (I added) nine pounds. I went from, like, 240 to 249."

Here's a look at Thomas' 2024 season and his outlook this fall:

Tackles: 23

Tackles for loss: 12.5 (15th nationally)

Sacks: 9 (20th nationally, 5th SEC)

Quarterback hurries: 11

Forced fumbles: 2

Fumble recoveries: 1

With Thomas in the fold, it answers a lot of questions for the defensive line.

Thomas immediately slots in as one of the starting defensive ends. He'll help anchor a defensive line that is retaining more talent and production than any other position group on the team. With Damonic Williams, Jayden Jackson, Gracen Halton and David Stone returning on the interior, Thomas gives the Sooners elite talent on the end and helps bring even more continuity on the line of scrimmage heading into a pivotal season.

Because outside of Thomas, the Sooners' defensive end group has a ton of questions despite there being clear potential and talent. The Sooners lost three-year starter Ethan Downs to graduation, along with rotation player Caiden Woullard. The Sooners have a few options at the other defensive end spot, including Marvin Jones Jr., PJ Adebawore, Danny Okoye, but Thomas' return gives the Sooners an elite, experienced and consistent option that they wouldn't have otherwise.

For Thomas, it'll simply be about building on last season. He's already established himself as one of the country's elite pass rushers, but there's room for growth when it comes to defending the run. He finished with a 64.4 run defense grade, per PFF, and a 52.2 tackling grade. His production also slipped just a bit as the season went on, logging just 3.5 sacks over the final eight games.

But those are all just nitpicks. Thomas is an elite defensive end, and if he builds on last season, he'll easily finish next season as one of the players in college football and an early NFL Draft pick.

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