The Cubs announced Friday afternoon that they acquired left-handed pitcher Derek Holland and cash considerations from the Giants in exchange for cash considerations. As a corresponding move, they removed reliever Tim Collins from the 40-man roster. Utility man Ian Happ is being activated on Friday, so Collins goes down for him while Holland travels to meet with his new team. When Holland is activated, presumably Saturday, the Cubs will need to make another roster move.
Holland likely slides into the role vacated by lefty Mike Montgomery, which is serving out of the bullpen with the option to be a long reliever or even a spot starter.
Holland's numbers this season look pretty ugly: 5.90 ERA, 71 ERA+, 6.08 FIP, 1.50 WHIP. There is a saving grace and likely this is what the Cubs saw. Holland has held lefties to a .182/.276/.195 slash this season.
Kyle Ryan has been good this season and he's really the only reliable lefty the Cubs have been able to use out of the bullpen. Now there's Holland as the second lefty option and if the Cubs stick to just using him as a LOOGY and those numbers against lefties hold, he'll likely be effective.
If the Cubs are hoping for more -- as noted above with spot starts -- it doesn't seem like the results will be good, but I suppose they could be hoping Holland reverts back to what he was last season for the Giants (3.57 ERA, 106 ERA+ in 171 1/3 innings).
Regardless, don't count on this being the biggest move the Cubs make in front of the July 31 trade deadline. This is adding at the edges for the purposes of depth.