MLB

Age, better competition big challenges for Yankees

Kerry Wood (Charles Wenzelberg/New York Post)

For much of this summer, the Yankees have had the best record in the majors. They also have possessed the best run differential, often the best barometer of overall ability.

So why on so many days do the Yanks seem to be playing in slow motion? Why does it feel as if they have so many troubling elements that promise to derail them between now and The Canyon of Heroes?

Are they just scored with a higher degree of difficulty? Could it just be that if you stare at any team long enough — including the 1998 Yankees — you will find flaws? Or does this team have, at the very least, more significant defects than last year’s champions?

BOX SCORE

“I think our team is stronger than last year’s team,” GM Brian Cashman said. “When you judge yourself, your assessments are harsher whether it is the team doing it, the media or the fans. But I think if you take a step back, you see that we are deeper in pitching than last year, have a better defense and a terrific offense. I do agree, we have not maximized our potential, but we are still pretty damn good.”

The Yankees began play yesterday with a one-game lead over the Rays in the AL East. On July 23 (through 95 games), the Yanks led the division by four games, their biggest edge of the season. Only twice since divisional play began in 1969 have the Yankees had a lead that large and not won the division.

In 1973, they led the AL East by four games through July 2 (99 games). In 1987, the Yanks led by five games through July 5 (82 games). Both years, the Yanks wound up fourth, so they wouldn’t have been a wild card even if there were such a thing then.

This year the largest separation between the Yankees and falling behind the wild-card leader was an eight-game gap on July 26. They went into yesterday with a 6 1⁄2-game edge over Boston, the AL team with the best record not currently in playoff position.

Through 123 games last year, the Yankees were 77-46 compared to a near-identical 76-47 this season. But they already led the AL East by 61⁄2 games and were 81⁄2 games up on any playoff spot. The Rays were third in the AL East at 67-55, not much different than the fourth-place Blue Jays (64-57) are this year.

“We are better, but our competition is much better, too,” Cashman said. “That is what makes our record even more impressive — because our competition is so much tougher. Toronto is in fourth place in our division, and I think if you put them in a lot of other divisions, they win it. The East is a beast.”

As a way to better figure out who the Yankees are over the final five weeks, let’s put various items under the microscope:

ROTATION

No phase provides greater worry. It feels like CC Sabathia and the Pips. But Cashman claims that is unfair, that if you look at a snapshot of a moment it does not provide a full picture. He says there have been stretches of this year in which A.J. Burnett or Javier Vazquez has been the Yankees’ best starter.

The Yanks do not plan on having Andy Pettitte before September, but they do plan on having him for October.

“Pettitte is not going to have a season-ending groin injury,” Cashman said.

In the meantime, Cashman was proud of Dustin Moseley “allowing Pettitte time to heal and helping us win games. That is awesome.” The Yanks were 3-2 in Moseley’s first five starts. Obviously, the Yanks had hoped to finalize a trade for Cliff Lee that they were on the precipice of completing. Lee went to Texas and, amazingly, the Rangers are just 3-6 in his first nine starts.

Phil Hughes is at 1402⁄3 innings. The Yanks probably will cap him at about 175. But what if they want to start him in the playoffs?

“In playoffs it is all hands on deck,” Cashman said. “All restrictions come off. He has a regular-season innings limit, but no limitations in the postseason. How can I look anyone in this organization in the eye if we put restrictions on winning games in October? So there are no restrictions.”

The Yanks won in the postseason using just three starters last year. The scheduling this season will not allow that. The reality is that the Yanks might have the fourth-best rotation in the AL East, and Burnett and Vazquez have two of the 12 worst ERAs in the league. After Sabathia, there is going to be a lot of hoping, praying and . . .

BULLPEN

The Yanks may have to use a formula similar to 1996. The rotation pitched to a 5.03 ERA in 15 playoff games that year with Kenny Rogers a disaster (three starts, none more than three innings, 14.14 ERA). Yet the Yanks won all three of Rogers’ starts and went 11-4 in October. That is because the ’pen worked to a 1.81 ERA.

And it was an entire ’pen. David Weathers, for example, never pitched well for the Yanks in the regular season, but was very valuable in that postseason. Graeme Lloyd went from almost not making the postseason roster to a force. Mo Rivera was, as always, great, and John Wetteland went 7-for-7 in saves.

Bullpens tend to be fickle, so what is occurring now might not last through the postseason. Still, since the July 31 acquisition of Kerry Wood, the Yanks’ bullpen has been deep and effective, and Cashman believes the injured Alfredo Aceves and Damaso Marte (the Lloyd of last year’s postseason for the Yanks) will be back for the playoffs.

OFFENSE

Here is a major perception-vs.-reality issue. The Yanks’ offense clearly is inferior to last year’s. But offense is down throughout the majors, and the Yanks — like last year — still lead in runs. Last year, though, they juiced the home crowd with 15 walk-off wins compared to just three this season.

“We don’t have the historic walk-off wins, but that just means we are less dramatic and have fewer pies in the face,” Cashman said. “We are just winning heading to the last inning more often.”

AGE

This factors into every Yankee issue. Last year, the Core Four was almost magically invigorated by the opening of the new Stadium, and they had seasons and health reminiscent of their primes. This season, only the android known as Rivera has been age-proof. Pettitte is out with the groin injury, and Derek Jeter and Jorge Posada are inferior to last season, with Jeter having arguably his worst campaign ever. Alex Rodriguez, 35, also has been nowhere near his prime with his health or production, and needed to go on the DL yesterday due to recurring problems with a calf injury.

Again some perspective might be necessary. Jeter’s .727 OPS is a career blight, but still is second among AL shortstops. A-Rod’s .820 OPS is third among third baseman in the AL as is Posada’s .818 OPS among AL catchers (minimum 300 plate appearances).

The Yanks, however, must nurse older bodies the rest of the way and hope that the adrenaline of playoff time enlivens their veterans. Remember that a huge reason the Yanks won it all last year was that their great players (Sabathia, Pettitte, Rivera, A-Rod, Jeter) played great.

SCHEDULE

Beginning tomorrow, the only team left on the Yankees’ schedule that entered the weekend with a losing record is Baltimore. And this version of the Orioles, under Buck Showalter, is different from the first-half patsies.

The Yanks’ final 13 games are against the Rays, Red Sox and Blue Jays, which poses a potentially lethal close. Consider that the Rays play four in The Bronx from Sept. 20-23 and then their final 10 games are against bottom-feeding Seattle, Baltimore and Kansas City. So the Yanks probably had better have some cushion with 10 to play if they are going to win the division.

If the Red Sox can just hang close to the Yanks, they potentially could determine their own fate because six of their final 10 games are against the Yanks, including three in The Bronx to close the year.

The ultimate spoiler here is Toronto. Beginning with this weekend, half of the Blue Jays’ 42 games left were against the top three teams in the division, including nine (the most) against the Yankees. And the Jays are a spry underdog. They headed into yesterday with the best record (20-12) in the AL East since the All-Star break.

joel.sherman@nypost.com