Denver Broncos running back C.J. Anderson will undergo arthroscopic surgery on his right knee on Thursday that could end his season.
Anderson was injured on an 11-yard run on Monday night against the Houston Texans but returned to the game and ran 14 more times for 84 yards and a TD, finishing with 107 yards in his best performance of the season.
Reports earlier in the week suggested Anderson had a bone bruise and might be fit to return in a few weeks but a second opinion has confirmed the damage was worse than initially feared.
Once surgeons assess the damage to his knee they will determine if his season is over but Anderson is holding out hope he will be able to return later in the season and help the Broncos to reach Super Bowl 51.
Anderson wrote on Twitter: "I just want to thank my team-mates, friends, family and coaches for helping me get through this process. I have the greatest organisation in the Denver Broncos that will help me be back stronger than ever.
"To all my fans thank you for the love and the prayers I have been receiving in the last couple hours.
"We will not know until after the procedure if I am done for the season or if I can come back to help my team to #51. Just know I will grind and push to be the best always and be stronger than I was before."
In Anderson's absence, rookie running back Devontae Booker will be elevated to the feature back role for the Broncos, with third-year player Kapri Bibbs backing him up.
Booker had his best game of the season on Monday with 17 carries for 83 yards and a touchdown in the 27-9 win over Houston and is averaging an impressive 4.8 yards per carry for the season.