On February 7, 2004, about 1430 mountain standard time, a Mooney M20C, N9675M, collided with a taxiway sign following a loss of directional control while on the landing roll at Falcon Field Airport (FFZ), Mesa, Arizona. The pilot/owner was operating the airplane under the provisions of 14 CFR Part 91. The private pilot and one passenger were not injured; the airplane sustained substantial damage. The local personal flight departed FFZ about 1330. Day visual meteorological conditions prevailed, and a flight plan had not been filed. In a written statement, the pilot reported that he had been cleared to land on runway 22L. The airplane touched down on centerline, with the main landing gear making contact with the runway first, and the nose wheel following. During the landing roll, the airplane made a sharp left turn. The pilot did not apply rudder pressure to counteract the veer. The airplane departed the left side of the runway and collided with a taxiway sign. The airplane sustained substantial damage to the inboard section of the left wing and ruptured the left fuel tank. The pilot reported no preimpact mechanical malfunctions or failures with the airplane. An aviation routine weather report (METAR) for FFZ at 1441 reported winds from 130 degrees at 6 knots and visibility at 50 statute miles.