As expected, the Mariners did indeed select a player in the Major League phase of Thursday’s Rule 5 Draft, plucking RHP Brandon Brennan out of the Colorado Rockies farm system. He had signed a minor league deal with the Rockies on November 13 after previously spending his entire career in the White Sox organization.
After being selected in the 4th round of the 2012 draft out of Orange Coast College—he transferred there after redshirting one season at the University of Oregon—Brennan continued to see work as a starter through the first four years of his professional career before beginning the transition to a relief role upon a midseason promotion to Double-A in 2016.