Investigators said they found no evidence that Ohio State failed to properly monitor its football program or any evidence of a lack of institutional control, according to a letter sent to the university and released Friday.
NCAA investigators also said they have not found any new violations.
"Considering the institution's rules education and monitoring efforts, the enforcement staff did not believe a failure to monitor charge was appropriate in this case," the NCAA said in the letter sent Thursday.
The notice clearing Ohio State of the most serious of institutional breaches is a big break for the university, which will meet with the NCAA's committee on infractions on Aug. 12. That committee could accept penalties Ohio State already placed on itself or could pile on recruiting restrictions, bowl bans and other, stiffer sanctions.
The NCAA letter first reported by The Columbus Dispatch said that Tressel was the only university official who knew about the violations involving his players. He didn't report them to anyone else at the school.
Ohio State spokesman Jim Lynch said the NCAA's findings were consistent with the university's own investigation into what happened with the allegations surrounding Tressel and the players.
Tressel stepped down under pressure in May, months after the university discovered emails showing he'd been warned by an attorney in April 2010 about his players' involvement with a Columbus tattoo parlor owner. The coach knew players received cash and tattoos for autographs, championship rings and equipment but did not tell anyone at Ohio State or the NCAA for about nine months. NCAA rules — and Tressel's contract — specified that he had to disclose any and all information about possible violations.
The university announced earlier this month it would vacate the 2010 season, including its Sugar Bowl victory over Arkansas and its share of the Big Ten championship. It also self-imposed a two-year NCAA probation, in addition to suspending six players for the first five games and forcing Tressel out.
Ohio State also will overhaul its compliance office by the end of the year, creating a centralized office that will oversee athletics as well as other university departments, one of its trustees announced Friday. The move will strengthen oversight of all aspects of the university, said trustee Robert Schottenstein.
Shortly after Tressel ended his 10-year run at Ohio State, which included the 2002 national championship, star quarterback Terrelle Pryor — one of the suspended players — left the school, hoping to try his luck in an NFL supplemental draft.
Tressel met with Ohio State and NCAA officials on Feb. 8 to discuss the allegations. According to a transcript released Friday, he said that he made a mistake by keeping the information from his superiors.
He also said he knew that NCAA sanctions were "inevitable."
"It was pretty simple. We were either gonna be horribly in trouble from a criminal standpoint, or we're gonna be minorly involved in drug, you know, buying and stuff, or we're gonna face the NCAA reality that we did some things with our memorabilia we're not allowed to do," he said. "I was totally confident one of those was gonna happen."
The U.S. attorney's office notified Ohio State officials last December that it discovered some Ohio State memorabilia during a raid. That led to the investigation into five players who were suspended, but allowed to participate in the Sugar Bowl on Jan. 4.
Tressel was asked if he would have never come forward if the government had not sent the letter. "Never is a long time. I don't know," he replied.
"I had confidence in the federal government that they were gonna do what they were supposed to do," he said. "They didn't need my help to do it, nor did they need my interruption to do it."
The NCAA also said in its letter released Friday that it investigated a Sports Illustrated report that said nine more players sold memorabilia to the tattoo parlor owner, but confirmed that only one had any dealings with the man.