The verdict is in: the reliever dumped to make room for the 13th position player (newly-claimed outfielder Cole Gillespie) is Henry Rodriguez, per Carrie Muskat.
Although he was worth picking up in a minor trade from the Nationals earlier this year thanks to the live arm and raw ability that you can’t teach, the problems that led to Rodriguez being dumped by the Nats in the first place persisted (i.e., he walked four in four innings, and didn’t have great command). Dale Sveum never seemed to trust him (he’s been with the Cubs over a month and has pitched just five times), and now the Cubs will figure out what they’re going to do with him. The designation for assignment was required because Rodriguez was out of options – in other words, this is about the 25-man spot, not the 40-man spot (which the Cubs already had available for Gillespie – meaning this move takes things down to 39).
The Cubs will have 10 days to trade, release, or waive Rodriguez, but you can expect they’ll try and get him through waivers. He’s worth keeping in the organization, and maybe the Cubs can work some magic on him at AAA Iowa. In some ways, this may have always been the plan when Rodriguez was picked up in the first place.