Six-time Pro Bowl running-back Peterson, 29, appeared in court in Houston, having been arrested in September on suspicion of causing physical harm to his son.
Peterson's plea agreement lessens the felony charge he had faced and also expedites a possible return to action with the Minnesota Vikings.
Peterson has not played for the team since the charges were revealed.
A trial date was initially set for December 1, but the plea deal accelerated the case and has now sets things in motion for a possible return to the NFL this season.
"I truly regret this incident," Peterson told reporters outside the courthouse.
"I stand here and take full responsibility for my actions. I love my son more than any one of you could even imagine. I am looking forward to and I am anxious to continue my relationship with my child.
"I am just glad this is over. I can put this behind me and me and my family can begin to move forward."
The NFL released a statement Tuesday addressing the question of Peterson's future status.
"We will review the matter and make a determination," it read. "We cannot provide a timetable."