The Yankees have been fighting the forces of entropy and winning for nine years. Last night, the Yankees clinched their ninth consecutive division title. This is both an event and a non-event. Something that happens with the regularity of nine times in nine chances is routine; for nearly a decade the Yankees have been more dependable than the subway, and with recently announced MTA service cuts, the subway will not be challenging them for the title anytime soon.

At the same time, repeating is one of the hardest things to do in sports. It’s a cliché, but it’s true. Nature abhors anything that takes extra effort to achieve. High-energy systems want to revert to low-energy systems. Both bad and good baseball teams want to be average baseball teams. Everything pulls toward the center. The reasons that the Yankees have resisted that pull, be it because of a monetary advantage on the rest of baseball, baseball savvy, or dumb luck, doesn’t matter as much as the fact that they’ve done it. As with the long run of Braves National League East titles that the Mets ended this year, the number of contests won doesn’t matter much either, just that the franchise conquered what the sport within a sport called defying the law of averages, also known as endurance juggling.

Most teams don’t have a margin for error. A Carl Pavano hops in his sports car with a leggy model on the wrong night; a starting outfielder breaks his wrist while sliding after a ball; an internationally known superstar sulks for months at a time, and they fold. These sorts of things happen every year. With most teams they cripple rather than wound, as they did this year’s Yankees.

Now that the Yankees are in the playoffs, anything can happen. It’s apparent that they and the Mets are the best teams in each league, but there is no guarantee that there will be another subway series at the end of the month (and with those service cutbacks maybe that’s not such a bad thing). The Yankees will apparently be gambling with a few playoff roster spots. If Gary Sheffield looks good at first base in the next couple of weeks, and Jason Giambi’s wrist doesn’t respond to a week or 10 days of rest, there could be a lot of Sheffield in the postseason, a Sheffield playing an unfamiliar position and swinging a bat that is rusty at best, hampered by injury at worst.

Another gamble will come with the outfield defensive alignment. Should both Sheffield and Giambi be available to play then the revived Hideki Matsui would get pushed back to the outfield. That would bench the team’s best defensive outfielder and put more pressure on the pitching staff. Another baseball cliché that doesn’t get enough play: Pitching is defense.The Yankees staff is not so good, nor so prolific with strikeouts, that it can afford to play an “offensive defense,” as Davey Johnson did in his Mets days by moving Howard Johnson to shortstop when strikeout/fly ball pitcher Sid Fernandez was pitching.

A third area that’s unsettled is the back end of the rotation. The Yankees can probably get through the postseason on four starters. Mike Mussina, Randy Johnson, and Chien-Ming Wang are certainties, but after them Joe Torre must weigh the value of experience versus recent success. Jaret Wright and Corey Lidle are veterans, but neither has been impressive, especially Lidle, who has been hampered by a finger injury that affects his pitches. Rookie Darrell Rasner is a talented fourth-fifth starting prospect who might have already been a sure thing for the postseason if he hadn’t gotten hurt just as the Yankees got interested in him. Finally healthy, he’s pitched quite well of late, but it’s dangerous to overestimate the significance of 17.2 major league innings. The Yankees would be wise to get him two more starts in the remaining games, if possible, but even then any judgment made on less than 30 innings is still going to be prone to a high degree of error.

That’s not to say that Torre shouldn’t pitch the hot hand, if instinct should lead him that way — and if a pitcher is going to give up five runs in five innings, it doesn’t matter if the pitcher is a veteran or a rookie. The question to be answered is whether Rasner has a better chance of not doing that than Lidle and Wright.

Jeff Karstens, another rookie starter who has pitched reasonably well and has roughly twice as many major league innings as Rasner to this point, is an even chancier option. He has a weaker minor league track record than Rasner and his time in the majors has shown him to be a pitch-to-contact type who allows a very high number of fly balls, a recipe for disaster in, say, a small ballpark against a team with power. Still, his ERA is 4.11, better than that of Lidle and Wright.

The bullpen also has some questions, starting with Mariano Rivera, who has been given September off in an effort to let him heal for the playoffs. There is no knowing if this idea will work — current suggestions are that it has, but we won’t know until he pitches a few times. Ron Villone has been a disaster of late, found pitcher Brian Bruney is unproved, and Scott Proctor may not have much left in the tank after throwing more than 100 innings in the regular season.

In 1927, the famous Murderers’ Row Yankees went through the entire year without making a single roster move. They won the pennant without trying, then swept their World Series opponent in four games.There was nothing for the manager to think about. He had his Babe Ruth and Lou Gehrig and Waite Hoyt, and he knew what to do with them. Things are far less certain for Joe Torre.

Mr. Goldman writes the Pinstriped Bible for www.yesnetwork.com and is the author of “Forging Genius,” a biography of Casey Stengel.