Indianapolis Colts running back Robert Turbin was suspended four games by the NFL on Friday for violating the league's policy on performance-enhancing drugs.
Turbin did not wait for a formal announcement by the NFL, instead posting on his Twitter account that his urine sample tested positive for a banned substance. He received a four-game suspension as a first-time offender.
The NFL made the suspension official later in the day.
"Today it will be made public, that a urine sample I provided to the NFL has resulted in a positive test of a banned substance under league policy with regards to Performance Enhancing Substances," Turbin wrote in a lengthy posting. "It absolutely kills me that I allowed this to happen. It has always been a priority in my life to display a high level of leadership both on and off the field. I strive to be a person that people can look up to and strive to exemplify the definition of hard work.
"Unfortunately, I have made a mistake. A mistake that will not only have personal consequences, but will affect the Colts organization, an organization that I am extremely appreciative to be a part of. For that, I am truly sorry."
The 28-year-old Turbin will miss games against the Cincinnati Bengals, Washington Redskins, Philadelphia Eagles and Houston Texans. He will be eligible to return against the New England Patriots on Oct. 4.
Turbin spent the last two seasons with the Colts, although he appeared in only six games before going on injured reserve in 2017 after sustaining a dislocated elbow. He took full responsibility for his actions in his Twitter post.
"Informing you all before the media is a huge priority for me. It is always essential for me to take ownership in any mistakes that I have made," Turbin wrote. "My hope is that through my mistake, we can continue to shine light on the importance of doing things the right way. I will continue to work diligently on correcting my error, assuring that this will never happen again.
"I will utilize this negative experience in my life by educating and informing others, with the hopes others will not put themselves in a similar situation."