Since Ruffin has less than three years of MLB service time and does not have a previous outright, he was automatically assigned to the AAA Tacoma Rainiers roster.
Ruffin made 9 relief appearances for the Mariners in 2013 going 0-2 with a 8.38 ERA (9 ER, 9.2 IP). He split the minor league season between AA Jackson (4-4, 3.90 ERA, 16 G/16 GS) and AAA Tacoma (1-2, 3.94 ERA, 15 G/2 GS). Ruffin was originally selected by the Detroit Tigers in the supplemental first round (48th overall) in the 2010 June Draft out of the University of Texas. He was acquired by the Mariners as the player-to-be-named later in a 6-player trade with the Tigers on July 30, 2011.