When the Yankees announced their $85 million signing of catcher Brian McCann earlier this week, owner Hal Steinbrenner cited the team's "singular and unwavering desire" to play deep into October. That desire likely will be mentioned again when the Yankees announce their seven-year, $153 million deal with ex-Red Sox outfielder Jacoby Ellsbury in the coming days.

But a look at the Yankees' finances reveals that a lust for trophies isn't the only thing fueling this free-agent splurge. When the Yankees fail to make...