For everyone who picked Marmol in fantasy, the answer whether Marmol would be the closer is answered. He will remain the setup man.
Kevin Gregg has been a monster during spring training, not allowing a single run. Marmol on the other hand has struggled, having an ERA of 4.50. What hurt Marmol was that he played in the WBC, while Gregg stayed and put out the show of his life.
Gregg has been improving as a pitcher, by lowing his HR allowed last year from 10 to three. His ERA went down from 3.54 ERA to 3.41 ERA. But I think this might just be a lucky statistic. Gregg has a high fly-ball to ground-ball rate, which won't work very well in Chicago.
This choice surprised many who who sure that Marmol would be closer, but he is just to good of a setup man.
For anyone who took Marmol in a draft, keep him. Gregg may struggle, and Marmol is second in line for the closer spot. Gregg is a flyball pitcher, and Chicago is not the place that you want this.
If Marmol is dropped in your league, I suggest picking him up, because he is just too good to not overtake Gregg during one point of the season.