Posey had already been suspended for the first five games of the year for his part in a scandal involving the sale of memorabilia. That incident cost Jim Tressel his job as head coach after it was learned he knew of violations by his players and failed to report them.
The NCAA said the latest problem for Posey involves his having received hundreds of dollars for work he did not perform.
Posey is eligible to play in only the final two games of Ohio State's season, one of them against Penn State Nov. 19.
"I am extremely disappointed with the NCAA's decision regarding DeVier Posey," Ohio State Athletic Director Gene Smith Friday. "This penalty is harsh considering the nature of the violation and the five-game suspension already served by this student-athlete."
The memorabilia incident caused quarterback Terrelle Pryor to leave the school for the NFL.