In 2021, Dondrea Tillman borrowed $2,500 from his grandmother. It turned out to be money very well spent.

Tillman had been a solid defensive lineman at Division II Indiana University of Pennsylvania from 2016-19, finishing fourth in school history with 30 sacks. But the coronavirus pandemic resulted in cancellation of his pro day in 2020 and he wasn’t selected in the NFL draft and had no teams bring him in for a workout.

In 2021, something called The Spring League was formed for NFL hopefuls. If Tillman wanted to play in it, he had to fork over some money.

“I had to pay $2,500,’’ Tillman said. “You had to pay to play. It meant that I had to bet on myself.”

Tillman borrowed the money from his grandmother, and it eventually paid off, although not right away. Tillman played for the Conquerors in The Spring League in Indianapolis and showed enough to be picked up by the Birmingham Stallions of the spring United States Football League in 2022.

Tillman had to toil for three years with the Stallions, the first two in the USFL and the third in 2024 in the United Football League after the USFL had merged with the XFL. But last June the Broncos signed Tillman, then 26. As a rookie, he had five sacks as a reserve outside linebacker while playing in 12 games and his future looks bright.

“I hope I’m inspiring a bunch of guys that went overlooked or happened to take the long road,’’ Tillman said of his journey. “You just got to keep working and your time will come. You just got to take advantage of each day. … Guys coming from (Division II), we have a chip on our shoulder. We have to work harder than everybody else just to be here.”

On Saturday night, the Broncos will take the field for their second of three preseason games, facing the Arizona Cardinals at Empower Field at Mile High. With Broncos coach Sean Payton having said most starters won’t play, Tillman, listed as second on the depth chart, should get plenty of snaps.

Watching from afar will be Zach Potter, general manager for football at Sacramento State University. Potter was the general manager when Tillman played for the Stallions and they won three titles, two in the USFL and one in the UFL.

“This guy defied all odds,’’ Potter said of Tillman’s road to the NFL. “This guy understood that life isn’t just over after X amount of years out of college football, that life isn’t over when you get told no multiple times.”

Tillman didn’t get any Division I offers coming out of Potomac Falls High School in Sterling, Va. He was a solid football and basketball player but said not many college football scouts showed up because Potomac Falls is regarded as “just a basketball school.”

Tillman chose to play in college for the Crimson Hawks over Slippery Rock, Gannon, Mercyhurst and California, and other Division II schools in Pennsylvania.

“Around my sophomore year (of 2017), some NFL scouts started coming to the facility and I thought, “I really have a shot at (the NFL),’’’ Tillman said. “But after my senior season, I didn’t have a pro day because of (the coronavirus pandemic).’’

So, Tillman didn’t play any football in the 2020 season and in 2021 participated in the six-game season in The Spring League. Tillman said that provided an opportunity to “get more film” out on him.

Potter was director of player personnel for The Spring League, so he got to see Tillman play plenty. After joining the Stallions in 2022, he sought to bring him to Birmingham.

There was a paperwork snafu and Tillman’s name wasn’t on the list for the 2022 USFL draft. But the Stallions were able to take him in the third round of a supplemental draft.

“He was a tweener,’’ Potter said of why other teams were not looking hard at Tillman.

The 6-foot-4 Tillman weighed about 270 pounds at the time. He was considered by some not heavy enough for the defensive line but too bulky to be an effective edge rusher.

Playing defensive end for the Stallions, Tillman led the USFL in pressures in 2022 although he had just 1.5 sacks. Tillman had four workouts after the season with NFL teams. Potter remembers talking to Tillman after one with the Pittsburgh Steelers.

“They told him, ‘Let’s add 30 pounds,’’’ Potter said about the athetic Tillman. “They wanted to see Dondrea play defensive tackle. He calls me and I told him, ‘You’re not a defensive tackle. You’re not wide enough and you don’t have enough twitch.”’

In his second season with the Stallions, Tilliman again led the USFL in pressures and increased his sack total to four. Tillman had two workouts with NFL teams after the 2023 season but still wasn’t signed.

“He came back (for the 2024 season), and he said, ‘I’m going to take it personal this year,’’’ Potter said. “So, he drew up an entire plan to have one great year, and he hires a trainer and completely changes his diet, and he played at about 255, 260 pounds. He lost some of that body fat.”

Tillman in 2024 had 3.5 sacks while starting all 10 regular-season games for the Stallions and was impressive in their two postseason games, getting two more sacks. That led to the Broncos after the season ended in June signing him to a three-year, $2.84 million contract that included a $10,000 signing bonus.

Tillman began last season on the practice squad before being signed to the 53-man roster prior to a Week 3 game at Tampa Bay. He then had two sacks against the Buccaneers in his first NFL game.

“It felt amazing, honestly,’’ Tillman said of his debut. “It meant the world to me just getting out there and playing fast and just playing free.”

Tillman’s five sacks last season came while playing a modest 242 snaps. Having a sack every 48.4 snaps was the best ratio on the team. It was even better than outside linebacker Nik Bonitto, who had a team-high 13.5 sacks in 708 plays, one every 52.4 snaps.

Tillman, now 27, has continued to work on his body. He is now listed at 247 pounds and considered a “tweener” no longer.

“It feels like I have come full circle, just starting from the bottom and just climbing up every day. Now, this is my second year, and I’m just trying to keep getting better.”

The Broncos are deep at outside linebacker with starters Bonitto and Jonathon Cooper, who had 10.5 sacks last season, and they also have Jonah Ellis, a third-round pick in 2024. But it might be hard for the Broncos to not give Tillman plenty of snaps this season.

“He’s out there hooping every single day,’’ Cooper said recently about Tillman’s play in practices. “If you really just sit back and watch him, he’s really crafting and really working.”

Broncos defensive end Zach Allen said “the story is crazy” how Tillman worked his way up from Division II to finally making the NFL five years after last playing in college. Denver tight ends coach Austin King, whose players go against Tillman regularly in practice, agrees.

“He’s an every-down player now who can contribute,’’ King said. “There’s plenty of guys that they’re fighting and clawing to get opportunities. … (Tillman’s story) is a testament to his mindset, his work ethic.”

As for the $2,500 Tillman once borrowed from his grandmother, Potter said he offered to pay it back, but she declined.