I met him at a fantasy camp game at Paul Owens Training Facility at Carpenter Complex in Clearwater, Florida in 2016, when fantasy campers from the New York Yankees, whom he was an instructor for, came to play fantasy campers from the Philadelphia Phillies.
Mickey signed a 2001 Topps American Pie card #60.
http://www.baseball-reference.com/players/r/rivermi01.shtml