The obvious thing to do in this situation is to look to how Phil Hughes rehabbed last year, but I’m not sure that makes a great comparison for Pineda’s situation. For one thing, I’m not exactly sure that they have the same injuries. Though Girardi has taken to saying that Hughes had tendinitis since Friday night, I don’t recall anyone saying that last April, and it would be awfully strange if we went through weeks of intensive tests trying to determine what the mystery ailment was only to find out it was a simple case of tendinitis. To say nothing of the fact that the MRI he had after his final April start didn’t show tendinitis either. Beyond the diagnosis itself, however, the immediate response to Hughes’ problem was to have him throwing bullpens, attempting to build his arm strength back up. Suffice it to say, that would not be an effective way to treat tendinitis, so the time Hughes spent on the DL before being shut down should be discounted altogether for our purposes.
Here’s what we know for sure: Pineda will be shut down entirely for about two weeks to allow his shoulder time to heal. After that, he’ll need to begin a throwing program to strengthen his arm again, and then he’ll probably throw some rehab starts in the minors before he comes back to the major league team. How long that takes will depend on how much work Pineda’s arm needs to get back in shape, but I would be surprised if it took as long as Hughes needed. After all, Pineda was running his fastball up to 93-94 in his penultimate start and was showing some signs of progress before the bottom fell out on him against the Phillies, atwhich point he was immediately sent for an MRI (you’ll remember that the Yankees were surprisingly reluctant to have an MRI done on Hughes last April) and has been shut down ever since. Pineda’s rehab, in other words, is off to a much better start than Hughes’ was last April and, at the very least, he won’t be doing the extra damage to his shoulder that Hughes was likely enduring once the regular season started. My best guess is that, barring any setbacks, Pineda will need two to three weeks of throwing followed by one or two rehab starts after his two week rest period to get his arm back in shape to pitch in the majors. That would put us right in the window of 5-6 total weeks of rehab that Girardi mentioned for when Pineda could return.
One thing to remember about all of this: Pineda will accrue major league service time while he’s on the disabled list/rehabbing in the minors, so the Yankees won’t stand to gain anything financially from dragging out his rehabilitation schedule.