Rebecca Dawson, 36, pleaded guilty to assault inflicting serious injury, a misdemeanor. She had been charged with malicious castration, a felony.
A jury deadlocked in the case last December, and a second trial was scheduled to begin Monday when the plea deal was reached.
Dawson was accused of using her fingernails to tear off Kevin Russ' scrotum at a Christmas party in 2006.
Prosecutors said Russ, 40, and Dawson were drinking at the party and got into a fight.
Russ said he was trying to keep Dawson from driving home because she had too much to drink when she clawed his face and grabbed his scrotum. The defense contended Dawson acted in self defense because she was being held after Russ wanted her to have sex with him and his girlfriend.
Dawson received a 75-day suspended jail sentence and was placed on 18 months of supervised probation. She was ordered not to drink alcohol while on probation, and she must complete an anger management course.