Even if Nelson is out until the beginning of July, the 5th starter will only make 10-15 starts. There's no indication that Suter/Woodruff wouldn't fill that gap. Then what, you're moving Chacin and his $8M salary to long relief in the bullpen? Again, if Anderson, Nelson and Davies show they are they pitchers they were last year, along with Chacin and MYSTERY PITCHER X, there's not an open rotation spot. And there wouldn't be for two seasons, since all (including Mr X, presumably) would be under control for that long. Now, if in the middle of the season, Anderson (or Davies) looks like last year was a fluke, or Nelson's rehab isn't going well, THEN you go after the second arm. To go after a second long-term controlled pitcher this offseason is a waste of assets.