Charles Joseph Riefenhauser (born January 30, 1990) is an American professional baseball pitcher.

That year he played for the Princeton Rays and the Bowling Green Hot Rods, and recorded a combined ERA of 2.25 with only 28.0 IP.

[5] In 2015, Riefenhauser made 17 appearances with the Rays, earning his first major league win on June 14 against the Chicago White Sox.

[6] On November 5, 2015, the Rays traded Riefenhauser, Nate Karns, and Boog Powell to the Seattle Mariners for Brad Miller, Danny Farquhar, and Logan Morrison.

[7] On December 2, before ever suiting up for the Mariners, Riefenhauser was the player to be named later traded along with Mark Trumbo to the Baltimore Orioles for Steve Clevenger.