Mark Thomas Teahen (born September 6, 1981) is an American-Canadian former professional baseball infielder who played in Major League Baseball (MLB) for the Kansas City Royals, Chicago White Sox, and Toronto Blue Jays. He graduated from Yucaipa High School in 1999 and attended St. Mary's College in California. Teahen was drafted 39th overall in the 2002 draft by the Oakland Athletics with a sandwich pick between the first and second rounds. He was featured in the book Moneyball, which noted the Athletics considered that Teahen could have the potential to become the next Jason Giambi. Prior to the 2009 World Baseball Classic, Teahen, whose father was born in St. Marys, Ontario, became a naturalized Canadian citizen and played for Team Canada in that event. In 2011, Teahen and Brett Lawrie both started in the infield for the Blue Jays, marking the first time the squad had two Canadians in its starting lineup. Professional career Kansas City Royals Oakland traded him to Kansas City in , along with Mike Wood, as part of a three-way trade that sent Carlos Beltrán to the Houston Astros, Octavio Dotel from the Astros to the Athletics, and John Buck from the Astros to the Royals. Although he had been one of the most highly regarded prospects in the Oakland organization, he became available when the Athletics were able to sign Eric Chavez to a long-term contract. Royals management did not expect Teahen to make the opening-day roster in ; however, after hitting .344 in spring training and after injuries sidelined potential third basemen Chris Truby and Chris Clapinski, the Royals announced Teahen would be their regular third baseman for 2005, and he made his major-league debut on April 4, 2005. His first hit was a triple and he hit four homers in his last 17 games of 2005. Teahen hit .240 in his rookie season with KC. In , he hit .290 with 18 home runs and 69 RBIs. During July, he raised his performance level with 10 home runs and 35 RBIs during the 38 games ending August 2. He continued to hit well, but suffered an injury and had to have season-ending surgery on September 8. Going into the season, Teahen moved from third base to right field because of the arrival of young prospect Alex Gordon. His home run total dropped alarmingly to only seven homers, after hitting 18 the year prior.