The ChiSox are putting together a very strong bullpen, after acquiring Robertson to be the closer. They also have Duke as a solid lefty reliever, so Jennings adds depth to that element of the 'pen. He should make the team out of spring training and is a bit underrated.

Rienzo adds depth to the Marlins' pitching staff, but his role is undefined at present time. There probably won't be room for him in the starting rotation if Miami is healthy going into 2015, but Rienzo has some experience pitching out of the bullpen as well. He's also still pretty young (26).

Jennings should play the role of situational lefty in Chicago, so his fantasy value remains fairly low. Rienzo isn't a dominant strikeout pitcher, so he isn't a great fantasy option either (even if he does land a spot in Miami's rotation).