Played high school ball in Minco and El Reno Oklahoma. His senior year he was named Oklahoma Gatorade Player of the Year. Shell was drafted straight out of high school in the 3rd round of the amateur draft by the Anaheim Angels. Shell pitched in the Angels organization from 2001–. In the off season of the 2007 season, Shell pitched for team USA and was the winning pitcher in the Gold Medal game verses Cuba. He became a minor league free agent after the 2007 season and signed a minor league contract with the Washington Nationals. On July 11, 2008, he set the Nationals' record for the longest save in club history. He pitched 3 scoreless innings against the Astros to get the record as well as his first career save. On April 29, 2009 Shell refused a minor league assignment and became a free agent. On May 2, 2009 Shell signed a minor league deal with the Seattle Mariners.