For those of you unfamiliar with economics, here is an excellent illustration of opportunity cost from Investopedia:
The opportunity cost of going to college is the money you would have earned if you worked instead. On the one hand, you lose four years of salary while getting your degree; on the other hand, you hope to earn more during your career, thanks to your education, to offset the lost wages.As of this moment, the Yankees have two holes to fill in the rotation (as well as a huge question mark with A.J. Burnett), and the expectation seems to be that Cliff Lee and Andy Pettitte will fill those slots admirably. With Lee, one can understand playing the waiting game - he is, without question, the best starter available. Pettitte, on the other hand, has a fair share of question marks and, at 39, may not have much left in the tank.
Here's another example: if a gardener decides to grow carrots, his or her opportunity cost is the alternative crop that might have been grown instead (potatoes, tomatoes, pumpkins, etc.).
In both cases, a choice between two options must be made. It would be an easy decision if you knew the end outcome; however, the risk that you could achieve greater "benefits" (be they monetary or otherwise) with another option is the opportunity cost.
To that end, I find myself wondering why the Yankees don't put a bit more pressure on Pettitte. With the team seemingly unwilling to kick-off the season without a 'sure thing' in the rotation, the front office has watched several prospective options slip through their (future) fingers. Jorge De La Rosa, Jon Garland, Hiroki Kuroda, Jake Westbrook, Aaron Harang, and Ted Lilly have already signed, and Freddy Garcia, Kevin Millwood, and Vicente Padilla are rumored to be close to deals, as well. That leaves a Carl Pavano redux as the best-case scenario should Andy Pettitte retire, followed by risks with Ben Sheets and Brandon Webb. To borrow from the gardener example, the Yankees are hoping their carrots will grow - in the meantime, other farmers have cornered the market on alternative crops.
In my mind, the Yankees could do a great deal worse than allowing Ivan Nova, David Phelps, and Joba Chamberlain (or others) to compete for the fifth starters role were Pettitte to retire - particularly if Cliff Lee and CC Sabathia are headlining the rotation. However, with the dwindling supply of viable arms on the market and the questions behind Sabathia and Phil Hughes, I cannot help but wonder why the Yankees would tempt fate.