In exchange for his plea, prosecutors dropped assault and tampering charges against Louis Irizarry.
"I accept full responsibility for my part in what happened," said Irizarry, who will report to begin his sentence next week. "I just want to do my time."
According to the Franklin County prosecutor's office, Irizarry could be released in six months.
Irizarry was already on probation when the May 1 robbery took place. He had been convicted of assault, negligent assault and disorderly conduct for his involvement in a fight in a campus dormitory in October 2003. He also spent three days in jail.
Another former OSU player, Ira Guilford, was sentenced to two years probation for his role in the incident. He was convicted of punching the student whose wallet Irizarry took. Guilford is currently serving 45 days of house arrest.
Guilford has said he wants to return to Ohio State and his attorney is working to get him re-enrolled.
Irizarry, a tight end from Youngstown, played in seven games in 2003, mostly on special teams. He transferred to Youngstown State over the summer. He also has indicated that he wants to resume his football career upon his release.