Little said the girlfriend told police she and Johnson have been in a relationship three years.
Johnson turned himself in to police Friday. A preliminary hearing was scheduled for Oct. 23.
At a postgame news conference Saturday, Temple coach Steve Addazio had no comment on Johnson's arrest or his status with the team after a 37-28 win against South Florida.
Temple spokesman Raymond Betzner said the girlfriend apparently lives in a building called The Edge, where the university leases several floors. But Betzner did not know if her apartment is on a floor leased by the university.