Marquez was originally a sandwich pick in 2004 by the Yankees, but went to the White Sox in 2008 in the Nick Swisher trade. He has pretty good control (3.2 BB/9 career) but gives up a boatload of hits (10 per nine career, 11+ per nine in AAA). Until AAA, he was pretty good at keeping the ball in the park, but that ended up being a problem as well (1.2/9, explaining his 5.52 ERA at that level).
Because he's had pretty mediocre to poor results at AAA over the last couple of years, he's bounced around a ton since 2011- first going back to the Yankees on a waiver claim, signing with Seattle for 2012, then going to Colorado after the Mariners released him in July.
My thought is maybe the Reds might have him work out of the bullpen, especially with the Pensacola bubble of starting prospects (Cingrani, Corcino, etc.) along with Todd Redmond and Pedro Villareal still around. Marquez has never had a protracted stint in relief, yet he has something
scouts must like (high draft pick, keeps getting jobs despite poor numbers at high levels).