Rusty Hardin said Peterson finished one-third of his probation and its terms, which allowed him to apply for early termination.
"My main thing was making sure my obligations got completed, and that's what I did," Peterson said. "Early termination is what I was aiming for, and it worked out."
Peterson is done with probation nine months after he pleaded no contest to recklessly injuring his son by striking him with a wooden switch.
His probation also included 80 hours of community service, a $4,000 fine and counseling. He said that he did not want to do a public service announcement.
Hardin told the Star Tribune that a judge in Texas agreed that Peterson fulfilled the requirements of his probation and signed the early termination order late last week.
Peterson has rejoined the Vikings at training camp in Mankato after playing only the first game of the 2014 season.
ESPN's Ben Goessling and The Associated Press contributed to this report.