Alfred George "J.R." Mathes (born November 9, 1981, in Granger, Indiana) is a left-handed pitcher for the Camden Riversharks organization.Alfred George Mathes was nicknamed "J. R." by his grandmother after the character J. R. Ewing from the CBS television series Dallas.mMathes attended Elkhart Memorial High School, where he was recruited as a student athlete to Western Michigan University. He majored in computer information systems and business. He was drafted in the 16th round of the 2004 Major League Baseball Draft scouted by Stan Zielinski.
While at Western Michigan, Mathes was selected to the 2004 All-Mid-American Conference Second Team.
After signing in 2004, Mathes was assigned to the Arizona League Cubs, where he started his professional career. He was soon promoted to the Short-Season A Northwest League Boise Hawks, which won the league championship with a record of 3-0.
After the conclusion of spring training 2005, Mathis was assigned to the Florida State League Daytona Cubs High-A affiliate where he went 11-8. In 2006 his assignment was the Double-A affiliate West Tennessee Diamond Jaxx of the Southern League where his record was 10-8. From 2007-10 Mathes' career was spent in Des Moines, Iowa with the Pacific Coast League Iowa Cubs. His win against the Round Rock Express on July 23, 2010 put him on top of the franchise all time wins leader board at 38. He finished the season with 40 wins as an I-Cub.