Who were those men on the field at Citizens Bank Park last week, and what had they done with the Phillies?

After sweeping the San Diego Padres, splitting four games at Dodger Stadium and closing with two consecutive-extra inning wins that embarrassed the Mets at Citi Field, the defending champs swaggered home for three interleague series. The 7-3 road trip seemed to solidify their position as one of the best teams in the National League, if not all of baseball.

Then the American League East came to town and exposed the Phillies' holes while creating a few more. First, the Boston Red Sox snatched two of three games. That seemed understandable; the Sox are the team of the decade, after all. When Toronto swept the next series, that successful road trip began to feel like a far-off memory, and when Baltimore - Baltimore! - took three of three over the weekend, that feel-good journey seemed nothing more than a pleasant, fuzzy dream.

So what's going on? How to explain the bipolar Phils? And how concerned should the team be about last week?

Some of the problems related to injuries will soon pass, though their effects may linger. But other issues, particularly the ongoing struggles of leadoff hitter Jimmy Rollins and an awful home record, have lasted too long to be dismissed.

The Phillies recently lost Brad Lidge, Scott Eyre and Raul Ibanez to the disabled list. The pitchers hope to return next week, though Ibanez's prognosis in recovering from a groin strain is less certain. The Phillies will be glad to see their injured pitchers, because they have suffered without them.

Impatient fans who called for Lidge's ouster after the closer blew his fifth and sixth saves of the season in Los Angeles have now glimpsed life without him. The main problem has actually not been Ryan Madson's two blown saves and one loss since Lidge went to the DL with a right-knee strain. Madson is a quality reliever who would likely succeed as a closer if given an extended chance. The problem, exacerbated by Eyre's calf strain, has been a thinning of the already tired relief corps.

Prodded into frequent action by a flawed starting rotation, the Phillies bullpen has already thrown 2292/3 innings, the fifth most of 16 National League teams. Relievers will never admit when they are tired or hurting; that's the bullpen code. But Lidge and Eyre both used the word "tired" last week to describe their mates who have been left with an increased workload in their absence.

Though the team will be better with the upcoming returns of Lidge (perhaps as early as Wednesday, if a planned rehabilitation assignment in Clearwater, Fla. goes well today) and Eyre (possibly this weekend, likely early next week), the other tired bodies in the pen will not soon heal. Early-season bullpen burnout can bite a team in the fall and could well be the most lasting effect of the Phils' recent troubles.

Of course, the Phillies played most of last week without Raul Ibanez and most of the weekend without Ryan Howard. Howard was limited to a pinch-hit home run on Saturday but has apparently recovered from acute sinusitis. Ibanez, a revelation all season, has been missed, and comeback wins have vanished without him. While the Phillies hope his injury will heal by the end of his 15-day DL stint, they admit that the leftfielder could be out longer.

The Baltimore sweep needs to be placed in context. The Phils had no closer and a lineup missing two All-Star-caliber hitters. But the rest of the week, and their 13-22 home record on the season, were more troubling. As manager Charlie Manuel has pointed out, the Phils have too often failed to combine strong pitching and hitting in the same game. Rollins, hitless in the Baltimore series, has given his team a .261 on-base percentage from the leadoff spot.

Rollins has made a number of adjustments in recent weeks, and Manuel has expressed continued confidence that the shortstop will reverse his season. In the meantime, however, the Phillies' strong offense is severely hampered by weakness at the top. With Ibanez gone, the team has one fewer hitter to compensate for the vanishing Rollins, and the shortstop's effect on the lineup has become more pronounced.

The phrase "It's a long season" became a cliché because it is true. A good team does not allow its self-esteem to rise and fall with weekly streaks, just as a wise politician does not govern by looking at daily opinion polls. But the Phillies are 26-29 against opponents who are not the Washington Nationals. While far from the only team with problems, the Phils have seen theirs become much more glaring of late.

Contact staff writer Andy Martino at 215-854-4874 or amartino@phillynews.com.