The simple answer is yes.  However, a physical therapist in the state of Oklahoma can evaluate a person without a doctor's referral, but cannot legally provide treatment to that individual unless a doctor approves a treatment plan developed and provided by the physical therapist.

Currently, the national and state boards for physical therapy are working to obtain something called "Direct Access" for Oklahoma which would allow a physical therapist to treat an individual without a referral.  Currently, more than 40 states already have "Direct Access".