Ryan Howard, left, and manager Charlie Manuel watch batting practice during spring training. Howard’s recovery from surgery to repair a ruptured Achilles’ heel has been set back weeks by an infection. (Matt Slocum/AP)

One year ago, the Philadelphia Phillies were declared a dynasty by decree. Their “Four Aces” were on every magazine cover. Never had baseball witnessed such a starting rotation. Cancel the season. And for the rest of the poor NL East, go ahead and erase the next several years, too.

Baseball must despise a sure thing. The Phils are still a sane pick to be in the World Series. But they also might not even win their own division. With a speed that is chilling, the gap between the Phils and the rest of the NL East — much less all of baseball — has shrunk to the point where this season, or very soon, the young, rising Braves, Nationals and Marlins, or all three of them, may be on the Phils’ aging heels.

Life is about to get harder, for all those teams, because they have to play each other 54 times before they escape their division. But the Phils may feel it most because they’re everybody’s bull’s-eye. Kill the hegemony headlines.

This week, Phils shortstop Jimmy Rollins said he thinks slugger Ryan Howard might be lost for the entire ’12 season. The Phils officially disagree, saying the giant’s recovery from surgery to repair a ruptured Achilles’ heel has been set back weeks by an infection but that he will be back in . . . May, June, July . . . one of those months without an “r” in it.

“If you ask me, with this infection [to the skin on his left ankle], I don’t know if he’s going to play this year,” Rollins told ESPN, noting how each setback, with Howard now in a walking boot, means atrophy for the leg and the need to restart the whole process of getting back into baseball condition. The Phils’ first base hold-the-fort solution: ex-Orioles journeyman Ty Wigginton and, maybe once a week, Jim Thome if he can still play the field at 41.

Also, Roy Halladay just got hammered for the third straight time in spring training while scouts muttered about his decreased velocity. He has given up nine runs and five homers in 72 / 3 innings. It’s meaningless — unless it isn’t. Doc, 34, admitted the problem but vows his speed will return. Soon. Probably. He’s the best pitcher of the last five years; also the hardest used.

Chase Utley’s knee and hip are so chronically injured that, for the second straight spring, the Phils won’t even let him play an exhibition game. Last year, he batted only 398 times. Like Rollins and third baseman Placido Polanco, his offensive game is in an unmistakable multi-year decline.

Last winter, Roy Oswalt was deemed too old and injury prone to be re-signed, so the Phillies “Four Aces” are down to three. Cole Hamels, the trio’s only youngster, will be a free agent after this year. Two Aces?

Lots of teams have a few key players who are in their early 30s, but the Phils rely on 10 players who are 32 to 41. Five of them have $337 million in guaranteed long-term contracts, including $125 million to Howard. If the Phillies were any older, the club might have to change its logo to a lily.

This list of Phillie migraines grabs our attention and shows that the future, even tiny bits of it, are never promised to anyone in baseball.

Just six months ago, the Phils finished with 102 wins and the best regular season in their 129-year history. With their fifth straight NL East crown, maybe the Phils would rule for years. Didn’t the Braves win a division title 14 straight times?

Now, the conversation has changed. The Phils’ biggest challenge may not be October baseball. That’s when the power of Halladay, Cliff Lee and Hamels gives them maximum leverage. Philadelphia’s problem, more each year, will be getting to October at all. The exhausting regular season exposes the deterioration in their aging lineup and leaves them vulnerable to just one injury to their Big Three.

The Phillies’ run scoring has dropped from 892 in ’07 to a mere 713 last season; adjusted for their small home park, that’s below the major league average. Partly, that is a trend toward less offense in baseball, but mostly it is Philadelphia’s erosion, symbolized by its season-ending 1-0 loss at home to the Cardinals in Game 5 of the division series.

Because ’11 ended with such disappointment, it’s easy to forget how amazing the Phils pitching was last season — an outlier season; the Phillies had the lowest team ERA in the NL since the ’89 Dodgers. Everybody Manager Charlie Manuel handed a ball to was amazing, led by Halladay (2.35 ERA), Lee (2.40) and Hamels (2.79).

However, as a group, it’s unlikely they’ll match that standard. Several stat services predict performance for ’12 based on every geek factor under the sun: The Big Three project to about a 3.15 ERA. That’s excellent but would be 50 more runs allowed. If the Phils offense slips another notch, they are likely to be in a division dogfight this season.

Every year, baseball tempts us into false certainties. The day the Phils signed Lee for $120 million, they looked like they’d locked up multiple pennants. Not yet. Now, the Braves, Nats and Fish all look like they’re on the rise — and quickly. One of those hot teams will probably bomb out. The problem for the Phils is that all three of them are unlikely to flop.

Here’s what’s certain: Every day, the old core Philadelphia players get more ancient. Every day the young core players in Atlanta, Washington and Miami — probably in that order — get more polished. That trend may not dethrone the Phillies this year, but it will continue season after season.

The noise Philadelphia hears behind it this summer will not be footsteps. It’s more like a stampede. The Phillies should use that ruckus as motivation to reach another World Series if they still can. Because in the NL East it’s not going to get any quieter at the top.

For Thomas Boswell’s previous columns go to washingtonpost.com/