PHILADELPHIA -- Phillies manager Charlie Manuel isn't one to throw out excuses.

The veteran manager has seen enough over his time in baseball to know that streaks, both positive and negative, are inevitable over the course of a 162-game season. He long ago came to grips with the fact that there will be times pitchers throw instead of pitch and hitters fall into slumps for a period of time.

Still, he simply has no explanation for what the Phillies have gone through over their past eight games.

"I don't know what to say," Manuel said. "All I can say is we have some guys, [Ryan] Howard and [Chase] Utley who need to get their timing."

Timing is one thing, this is something completely different.

Houston continued to be the Phillies' version of kryptonite as the Astros finished a four-game sweep at Citizens Bank Park on Thursday by virtue of a 5-1 win. It's the Astros' first four-game sweep since they did the exact same thing to the Phillies on Sept. 4-7 in Houston last year. Over the course of the past eight games, the Phillies (70-57) struggled to score just 17 runs and in seven of those contests scored two or fewer runs.

Philadelphia now finds itself three games back of Atlanta in the National League East and a half-game behind San Francisco in the NL Wild Card race. Both teams were idle, leaving the Phillies with a five-hour flight to San Diego to contemplate what went wrong on a 10-game homestand -- which started off with consecutive wins over those same Giants, but ended with losses in five of the past six contests.

"You try to figure your way through it," shortstop Jimmy Rollins said.

Rollins also proved to be a bit of a historian as well. When asked what, if anything, he could point to as the Phillies' biggest hurdle he had the perfect one-word answer.

"Houston," Rollins said. "It's been a team that over the years has given us problems whether we were at home or in Houston. Doesn't matter if they are good or bad, they always give us problems."

With the current struggles offensively, the Phillies needed a shutdown afternoon from Kyle Kendrick (8-7) but the starter allowed single runs in each of the four innings as Houston built a 4-0 lead. Kendrick went six innings and allowed nine hits to go with those four runs, and while that should be good enough to win with what this offense looks like on paper, it wasn't enough on this day -- just as it hasn't been enough over the past eight games.

"Four runs over six innings isn't a quality start," Kendrick said. "I don't think it's horrible, but I don't think it was good."

Of more concern, the Phils have struggled to go just 21-19 against teams that are 10 or more games below .500. Granted, the offense has been plagued by injury all season, but the Philadelphia can only hope that now that its Opening Day lineup is back, it can find a rhythm that has made it one of the most feared in the game over the past two seasons.

Something many of the Astros are all too familiar with.

"It's always satisfying to beat a team that's contending, especially a team like that, that's been to the World Series two times in a row," said Michael Bourn, who went 3-for-5 on Thursday and gave the Phillies fits throughout the four-game set. "They don't like getting beat. I know them over there. We were trying to make them earn whatever they had to get, and we just kept it rolling from Game 1 and it paid off for us.

"We were playing a good team over there and we had to battle. It wasn't an easy team to beat. You've got to play all 27 outs. As you can see in the last inning, they still tried to come back. That's one thing about that team, they're not going to give up and I know that. Every game we have to focus for nine innings to beat that team, and we were able to do that every game and won four in a row."

That opens the door for a huge question when it comes to this version of the Phillies. This series was marred by some curious calls from the umpires, a lack of hitting, but most of all some plays that could only be characterized as the result of a lack of focus.

"I know we're better than that," Manuel said. "I want to see us start clicking. When you don't score runs it looks bad. It looks as if there is no life.

"There are no reasons to make mental mistakes. It's a sign of not being focused in the game. I think that comes into play and it's what you may want to call -- lackadaisical. I saw a lot of it [over the past week]."