A fight Friday afternoon in the yard at the Luther Luckett Correctional Complex in La Grange ended in a stabbing.
Officials said Justin Anderson, who is serving time for robbery and was eligible for release as soon as November, had an improvised weapon he used to attack Hershel Havens. Havens is serving time for drug charges until at least March of next year.
Havens was flown to University Hospital in Louisville for treatment of his serious injuries. He is expected to survive.
Anderson was hurt but is also expected to be OK, according to officials.
The prison was temporarily placed on lockdown so Kentucky State Police could investigate. No staff were hurt.