Former Denver Broncos running back Otis Armstrong has died at the age of 70, per a team announcement Friday.

According to Mike Klis of 9News, Armstrong died Wednesday evening surrounded by his wife, Yvonne, and family.

The former Purdue star was a first-team All-American in 1972 to cap a career that included 4,601 scrimmage yards and 24 scores. The Broncos selected the ex-Boilermaker with the No. 9 overall pick in the 1973 NFL draft.

As Nick Kosmider of The Athletic noted, Armstrong faced a tough assignment off the bat.

"From the time Armstrong entered the league, he was handed the unenviable task of following in the footsteps of Floyd Little, the star running back who became known as The Franchise for his contributions to a Broncos organization that was still coming of age in the late 1960s and early 1970s."

He took the reins of the Broncos backfield in 1974, when he paced the NFL in with 1,407 rushing yards and 5.3 yards per carry. Armstrong also added 38 catches for 405 yards and finished the year with 12 total touchdowns. No other NFL running back had more than 1,162 rushing yards (Don Woods of the San Diego Chargers).

The 1976 season ended with Armstrong's second and final Pro Bowl appearance thanks to 1,465 scrimmage yards (1,008 rushing, 457 receiving). He also had a career-high 39 receptions.

Armstrong led the 1977 AFC Champion Broncos in scrimmage yards (617), rushing yards (489) and co-led in total touchdowns (four). He notably had 53 total yards and a touchdown in a 34-21 win over the Pittsburgh Steelers in the AFC Divisional Round.

He ultimately had an eight-year NFL career spent entirely in Denver. Anderson finished his NFL tenure with 5,755 total yards and 32 touchdowns.

Some of Armstrong's teammates offered their remembrances.

"It's a very sad day," ex-Broncos wide receiver Haven Moses told Klis.

"Otis was a very special person. We had a very close team. Otis was a wonderful teammate, a wonderful running back. He'll definitely be missed. He was part of a Bronco era that laid the foundation for the team's success today."

Broncos offensive tackle Marv Montgomery added, per Klis: "I was thinking back to 1973 when Otis came to camp in his first year. I always remember how he ran. He was always on his toes. It was like a butterfly moving through the line. He had a very interesting way of running."

Per D.J. Fezler of Boilermakers Country, Armstrong is also a member of the College Hall of Fame as well as the Colorado Sports Hall of Fame. He lived near Denver after his NFL retirement.