Bristol County Sheriff Thomas Hodgson says the former New England Patriots tight end had an altercation with another inmate at the Bristol County House of Corrections on Tuesday.
Hodgson says jail staff are interviewing witnesses and reviewing surveillance video to figure out exactly what happened and determine whether charges are warranted.
A jail spokesman says neither inmate was seriously injured.
Hernandez is being held in a segregated housing unit with only a few other inmates.
The 24-year-old Hernandez has pleaded not guilty to murder in the killing of 27-year-old Odin Lloyd. The Boston man was dating the sister of Hernandez's fiancee.
