The former Razorbacks volleyball player was hired by Petrino at a salary of $55,735 on March 28. Dorrell, 25, and the 51-year-old Petrino exchanged more than 4,300 text messages and nearly 300 phone calls over the last seven months.
After the two were involved in a motorcycle accident, Petrino told police that he was the only one on the bike.
Petrino, who is married with four children, later admitted to a "previous inappropriate relationship" - but did not specifically divulge Dorrell as the other party.
