This would certainly qualify as finding rotation depth on the cheap. Per a report by Dan Martin, the Yankees were in attendance at Johan Santana's first Venezuelan Winter League start last night as he attempts to come back from a torn Achilles tendon. Santana pitched 2 scoreless innings and looked pretty good by most accounts. According to Martin, the Yankees are "intrigued" by the idea of signing Santana, and an unnamed source that they "will keep an eye on him."
Everybody knows Santana's story by now. He used to be the best pitcher alive not too many years ago, but a litany of major injuries put an end to that and have all but derailed his entire career. It's not just the comeback from the Achilles tear that factors into any decision on Santana, it's the torn shoulder capsule in 2011, the second torn shoulder capsule in 2013, and the back problems. Santana has been limited to 21 Major League starts since 2010, and at age 36 it's hard to imagine his body and its storied injury history holding up to any kind of consistent, regular workload.
There was a time where adding Johan Santana would have made sense, but today it really doesn't make any. He would only add to the injury risks and depth problems in the Yankee rotation, not help resolve them. If he holds up over the rest of the Winter League and the Yanks want to give him a ST invite and a MiL deal, fine. Anything more than that would be very unwise.