Injuries. Age. Financial prudence.
The increasing number of legitimate challengers throughout their division.
Something is as striking for the New York Yankees as that patriotic hat dangling atop the bat of their team logo: This could become the 1960s again, and those weren't glory days around the Bronx.
The bottom line is, the Yankees' latest dynasty is over. While others have gotten better, the Bronx Bombers have stayed the same or regressed. Plus, ownership is more into ... the bottom line.
There is nothing wrong with that, by the way.
That bottom line actually could be the Yankees' hope over the next few years. After all, this era is different from the free-spending one of the late George Steinbrenner, when you really could buy your way into prominence or somewhere in the vicinity.
Not only that, during much of the Boss's legendary reign with the Yanks from 1973 through his death in July 2010, baseball's luxury tax either didn't exist or was in its infancy.
Now the Boss's successors -- sons Hank and Hal -- prefer to keep the Yankees from the huge financial penalties associated with the luxury tax. It goes into effect for teams with payrolls above $189 million or so, and the Yanks' payroll often has surpassed $200 million.
The younger Steinbrenners wish to decrease their payroll by 2014. For inspiration, they needn't look further than their own American League East rivals, where the Tampa Bay Rays have made the playoffs three of the past five years -- including the World Series -- with a payroll nearly three times lower than that of the Yankees.
The Baltimore Orioles aren't big spenders, either, and they also rank among those rising in the division.
Elsewhere in baseball, the San Francisco Giants have won two of the last three World Series, and their projected 2013 payroll of around $140 million is slightly over half of what the Los Angeles Dodgers and the Yankees are expected to pay this season.
Even so, given those budget-conscious examples, and the desire of the younger Steinbrenners to follow them -- which entails pumping more resources into developing players through the Minor Leagues while staying millions shy of that luxury tax -- the younger Steinbrenners can't do what their father regularly did.
The Boss kept opening the Yankees' vault to fill holes, and the Yanks' current holes are gaping.
Earlier this week, general manager Brian Cashman said it is "more likely than not" that baseball icon Derek Jeter will start the season on the disabled list. He still is recovering from surgery on his left ankle that was broken during last year's playoffs.
So the Yankees will use a backup shortstop, and depending on Jeter's progress, that backup could become the regular for a while.
New York will also need a backup third baseman through the All-Star break -- or even longer. That's because Alex Rodriguez (hip) also is disabled. The same goes for first baseman Mark Teixeira (wrist) and center fielder Curtis Granderson (forearm).
Contrary to initial reports, Teixeira and Granderson will be gone closer to months instead of weeks, and they are two of the team's primary run producers.
Rodriguez also has been known to hit a few homers.
Jeter is Jeter, which means he is the ultimate Yankees captain, but he has another distinction: He joins pitchers Andy Pettitte, Mariano Rivera and Hiroki Kuroda and outfielder Ichiro Suzuki as players on the Yanks who were born at least 38 years ago.
This isn't to say the other key Yankees players are closer to rocking the cradle. Designated hitter Travis Hafner is 35, infielder Kevin Youkilis is 34 and CC Sabathia and Granderson are 32.
Perennial All-Star second baseman Robinson Cano is considered the baby of the bunch at 30.
Such age issues translate into the Yanks ending their recent dominance sooner rather than later. No, they haven't won a World Series since 2009, but they've averaged 96 victories per season during the past three years, and they've won the past two AL East titles.
The Toronto Blue Jays are loaded, though. They'll combine Jose Reyes and Emilio Bonifacio with Jose Bautista and Edwin Encarnacion for one of baseball's most potent lineups. They've also acquired NL Cy Young Award winner R.A. Dickey to enhance a pitching rotation that includes fellow offseason trade acquisitions Mark Buehrle and Josh Johnson.
The Red Sox only can improve from last season's bottom finish in the division. Their pitching looks solid, and new manager John Farrell is operating with less drama than Bobby Valentine, a noted instigator, who nevertheless inherited a messy clubhouse.
We've already discussed the Orioles and the Rays.
Which brings us back to the 1960s, when Mickey Mantle and Yogi Berra got old and creaky over night, while watching the competition improve in a hurry -- like these Yankees.
Those Yanks won a ninth pennant in 10 years, and then they lost the 1964 World Series before vanishing for a dozen years.
The Boss led the Yankees' revival in the 1970s with a slew of free-agent signings, and none was bigger than Reggie Jackson. From 1976-80, Mr. October helped the Yanks win their division four out of five years and capture three pennants and two World Series championships.
Here's the question: Given the Yankees' various obstacles and monetary restrictions these days, can the younger Steinbrenners trigger the franchise's next revival without suffering as long of a drought as it did between the 1960s and the '70s?
Don't know for sure.
What we do know is, as you were reading this, the Yankees' roster just got older and creakier.
Terence Moore is a columnist for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.