On June 29, 1996, about 2105 eastern daylight time, a Cessna 152, N48750, was substantially damaged when it struck a deer during the landing roll at Mansfield Municipal, Mansfield, Massachusetts. The private pilot and passenger were not injured. Visual meteorological conditions prevailed for the local flight. No flight plan was filed for the personal flight conducted under 14 CFR Part 91. The pilot reported that he conducted a scenic flight with his wife. They returned to Mansfield and performed an approach and landing to runway 14, a 3,498 foot long, 75 foot wide, runway. During the landing roll, the pilot observed a deer off the left side of the runway, and he added power to pass the deer. The pilot then felt and heard a bang. The airplane veered to the right and the pilot applied left rudder and brake; however, the airplane continued off the right side of the runway. The pilot's attempts to taxi the airplane were unsuccessful. Postaccident examination by a Federal Aviation Administration Inspector revealed that the vertical stabilizer was bent at an approximate angle of 45 degrees.