In case you haven't been keeping up with Joba's rehab from Tommy John, he provided an update early on Christmas Eve day the other day:
"Update on arm: feels great, throwing bullpens for a couple weeks. Now taking 2 weeks n resting my arm. Start throwing after the New Year"
If he's been throwing for a couple weeks already, that would put him ahead of schedule for his return. Instead of June-July, we could be seeing Joba back in the 'pen some time in May, assuming he continues to progress on his schedule and doesn't have any setbacks. As I've stated here before, he probably falls behind Mo, D-Rob, and Sour Puss in the bullpen hierarchy, making him more of a luxury than a vital piece at this point. But you never know what can happen with injuries, so the more late-inning depth the Yankees have, the better.