Mark Allan Hendrickson (born June 23, 1974, in Mount Vernon, Washington) is a Major League Baseball relief pitcher for the Baltimore Orioles. He is one of just 11 athletes to play in both Major League Baseball and the National Basketball Association.

Hendrickson was a three-sport standout in tennis, basketball, and baseball at Mount Vernon High School in the state of Washington. During his sophomore year, he was a member of the state championship baseball team and the runner-up state basketball team. He was a member of the state championship basketball team during his junior year, where he earned recognition as the co-MVP of the tournament for his play. He was also named team captain, team MVP, and named to the All-Area and All-State teams. A tennis state qualifier, Hendrickson was also named to the baseball All-Area team.

As a senior, Hendrickson led the Bulldogs to a second basketball championship. He was team captain, team MVP, All-Area, All-State, and the state basketball tournament MVP. For his performance on the basketball court, he was named the Gatorade State Player of the Year. In addition to his remarkable basketball play, he was able to help his team win the state championship in baseball, while also qualifying for state in tennis. He was named the Skagit Valley Herald Athlete of the Year both his junior and senior years.