Kolbe Katsis’ Historic Broncos Debut Puts Marvin Mims Jr. on Notice

The Denver Broncos were in another pickle on Sunday night against the Los Angeles Rams.

Two-time All-Pro returner Marvin Mims Jr. was ruled out of action for the second straight game, but this time, the Broncos had the wiggle room to elevate undrafted rookie returner Kolbe Katsis from the practice squad.

Katsis made his NFL debut under the primetime lights of Sunday Night Football, and he didn't disappoint. The rookie returned three punts for 39 yards (13 avg) and four kickoffs for 107 yards (26.8 avg).

The 146 return yards Katsis produced were the most by a returner making his debut in Broncos history. Entering Week 3, Goldie Sellers's debut of 144 return yards stood as the record since 1966.

In his NFL debut, #Broncos returner Kolbe Katsis finished with 146 return yards against the Rams (39 punt/107 kick).

That was the most by a Bronco returner making his NFL debut in team history. How's that for an auspicious development? pic.twitter.com/yUZ5DvdDHX
— Chad Jensen (@ChadNJensen) September 29, 2026

I don't think Katsis or the Broncos could have hoped for a more auspicious debut.

Broncos head coach Sean Payton liked seeing Katsis translate the returner "juice" he displayed in training camp and the preseason into his first NFL game.

“You never know in that first moment and you could see the preseason games, but the one return was the spark force, the punt return," Payton said of Katsis post-game. "I thought— you guys saw him in the preseason, you could see and feel the juice on the sidelines with the kick returns. I think it was good first night, if I’m him. He’ll probably sleep better than me.”

What Sparked the 'Spark'

The Broncos' decision to place rookie running back Jonah Coleman on injured reserve and sign long snapper Mitchell Fraboni to the active roster last week is what allowed Katsis to be elevated to the game-day roster. In the first two games, the Broncos had to use one of their two practice squad elevations on Fraboni because they couldn't play a game without a long snapper.

The Broncos elevated fullback Adam Prentice for the third time against the Rams and Katsis. Now, though, the Broncos have to either sign Prentice to the 53-man roster or waive him, since he's maxed out his three elevations.

The Broncos would prefer to just stash Prentice back on the practice squad, but they can't do it so easily this time; he'd have to first pass through waivers unclaimed before they could re-sign him. That's a big risk, which is why Denver could bite the bullet and sign him to the 53-man roster early this week, though doing so would first require a corresponding roster cut to make room.

Katsis' Path to Denver

Kolbe Katsis. — Kolbe Katsis sits on the bench during the preseason. | Hector Acevedo / IMAGO / ZUMA Press Wire

Broncos special teams coordinator Darren Rizzi identified Katsis in the draft earlier this year. The small-school product of Northern Arizona was signed as a college free agent after the draft, and it didn't take him long to make his presence felt in Denver.

Katsis, 24, really popped as a returner in the preseason games, raising questions about whether the Broncos would choose to keep him or veteran wideout Lil'Jordan Humphrey on the 53-man roster, since the rookie is a wide receiver by trade. The Broncos rolled the dice by keeping Humphrey and waiving Katsis at the final roster cuts, but the rookie passed through the wire unclaimed and was quickly re-signed to the practice squad.

Since then, Katsis has helped the Broncos prepare for each opponent on the scout team, biding his time for the first call-up of his NFL career.

The Mims Injury

Marvin Mims Jr. returns a kick in Week 1. | IMAGN IMAGES via Reuters Connect

One of the benefits of Katsis emerging is that it takes pressure off Mims to recover from his injury, but it only intensifies his contract-year status. In the preseason finale, Mims suffered a foot injury, though he was able to recover in time for Week 1.

Alas, Mims also injured his shoulder in the season opener, but he was able to finish the game. He hasn't played since then, though he was a limited participant in practice last week.

The signs are trending toward Mims being very close to returning, but there's no need to rush him now. The Broncos can elevate Katsis two more times before they'd have to either waive him or sign him, buying an additional window for Mims if he needs it.

The Takeaway

If I were Mims, I'd be a lot more anxious about getting back on the field after seeing Katsis perform in his debut. Mims has had some bad injury luck in his contract year, suffering a soft-tissue injury that kept him out for most of camp and the preseason, and now this foot issue.

If the Broncos choose not to re-sign Mims beyond 2026, it'll likely have something to do with Katsis. I hate to be so reductive, but that's the biggest value Mims brings to the Broncos — his returner ability — and while I'd love to see him be significantly more involved in the offense, this team has an embarrassment of riches at wide receiver.

I went into the 2026 summer feeling very optimistic about Mims getting extended, but the injury bug has extinguished it. Katsis's emergence has only further complicated the Mims situation, though the injury bug remains his biggest obstacle to an extension.

As for Katsis, congrats to the rookie for making the most of his opportunity last week. I'll be looking forward to seeing him on the field again — perhaps as soon as this week against the San Francisco 49ers.

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