Thomas was involved in a crash on Feb. 16, a few days after he was released by the Texans.
In a statement explaining the reasons for his arrest, police said Thomas was driving over 70 mph, more than twice the speed limit, around 12:20 a.m. near downtown Denver when his SUV went off the road and flipped end over end after hitting a median. The SUV landed on its wheels and one of his two passengers suffered serious injuries, the document said.
"It was important for me to accept responsibility for my careless driving. I personally promise I will never put anyone at risk with that type of driving going forward."Demaryius Thomas, in statement released by attorneys
Thomas will have to pay a $300 fine, complete 50 hours of community service and be on one year of probation. He also needs to pay court costs.
A felony reckless driving charge was dismissed.
"Many of the highlights of my life to date have taken place during my professional football career here with the Denver Broncos," Thomas said in a statement released by his attorneys.
"I will always consider Colorado to be a second home which I shall always remember with the fondest of memories. I have many close friends in Colorado who will continue to be a positive part of my life during and after my football career has finished. Many people reached out after my accident and I want thank everyone who has been supportive of my recovery. It was important for me to accept responsibility for my careless driving. I personally promise I will never put anyone at risk with that type of driving going forward. To you, the people of Colorado and Bronco fans, I say thank you for the memories. Perhaps we shall meet again."
Thomas, 31, played seven games for Houston last year, making 23 receptions for 275 yards and two touchdowns, before his season ended prematurely when he tore his left Achilles tendon.
In his nine pro seasons, Thomas has 688 catches for 9,330 yards with 62 touchdowns. He has made four Pro Bowls and won the Super Bowl following the 2015 season with the Broncos. Thomas was a first-round pick by the Broncos in 2010 and spent his career there before last year's trade. He is the second-leading receiver in Broncos history, with 9,055 yards and 60 touchdown receptions.
The Associated Press contributed to this report.