"Yes, we can," the manager said with conviction late yesterday afternoon at Yankees Stadium.

Pause.

"We can win it easier if he hits, though."

The Phillies trail the best-of-seven series, three games to two, despite getting little production from their cleanup hitter. And here's one of the mysteries of baseball: How can a hitter be so hot down the stretch (.316-19-59 in the last 50 regular-season games), in the NLDS against the Rockies (.375 with six RBI) and in the NLCS against the Dodgers (.333-2-8 and the previously mentioned MVP) and then turn so stone cold in the World Series?

There are no absolute answers. But here are five theories.

1 He's putting too much pressure on himself.

Manuel seems to subscribe to this school of thought. "I think it's only natural that you start trying harder [in the World Series]. And sometimes when you're trying harder, you're pressing and you try to do something [more] instead of being relaxed and staying focused. Because you feel like you've got to get going because it's the postseason.

"It's just about trying to get a good ball and being relaxed up there and keying in on what you're doing. Stay at it. Have a plan and stick to it. Have an idea of what you've got to do and let it happen. Play like you always do."

There's probably something to that. At the same time, there's no real reason for Howard to be tight. After all, he hit three homers and had six RBI in the World Series last year.

2 That's just baseball. Hitters go into slumps for no apparent reason and, unfortunately for Howard and the Phillies, it's happening during the most important games of the year.

Yankees first baseman Mark Teixeira can relate. He signed a huge free-agent contract last offseason. He'll get some consideration for American League MVP this year. And he's batting .105 in the World Series. The screaming headline on the back of yesterday's New York Daily News: $181M FOR THIS?

"Ryan and I are very similar players," he said before the Yankees worked out in preparation for Game 6 tonight. "When we get on hot streaks, it's tough to get us out and we can carry a team. But when you're a power hitter and try to hit home runs, when you try to drive in a lot of runs, you're also going to strike out.

"That's just the way it is. If you want Ryan Howard to hit .300 with 15 home runs a year, then he's not going to go through slumps. But this guy has put up bigger numbers than anybody in baseball over the last 5 years. It's going to happen every now and then."

3Howard lost his mojo during the week off between the time the Phillies clinched the pennant and when they started the World Series.

Manuel also said that Howard isn't tracking pitches the way he had been.

"When he's struggling, it's the pitcher and the fact that he's not following the ball," the manager said. "I can sit here and tell you exactly what gets Ryan in trouble. It's kind of up to him. The pitcher doesn't have nothing to do with it. Basically [when he's going well] he's just completely following the ball. He's staying on the ball, following the ball, and when he does that things usually come around for him."

4The Yankees pitchers are executing. Give them credit.

"I think we've made good pitches to him," Yankees manager Joe Girardi said. "I think we've changed speeds on him, I think we've moved the ball around on him. The bottom line is, I think we've made good pitches. He's an extremely dangerous hitter and if you don't make pitches, you're not going to get him out. He proved that in the first two rounds."

Added New York's Game 6 starter, Andy Pettitte: "I think we're making some pretty quality pitches against him. In the first game [CC Sabathia] left a few balls in the heart of the plate and he hit them hard. I don't think there have been a whole lot of balls left in the middle of the plate for him to hit."

Even Pedro Martinez, who will oppose Pettitte tonight, agrees with that. "You're talking about some of the biggest names in baseball pitching against one really good hitter. Out of that matchup, one of the two is going to have to fail and one is going to have success."

5 The Yankees have devised a better game plan to attack Howard's weaknesses.

Girardi downplayed the notion, going back to the idea that it's all about the execution. And it's true that the best scouting report in the world is useless if the pitchers can't or won't follow it.

Still, a look at how the Yankees have attacked Howard is interesting.

According to the breakdown on mlb.com, Howard has seen 92 pitches in the first five games. Thirty of them (32.6 percent) have been fastballs.

But, after they've gotten two strikes on him, they've thrown 33 pitches. Only six (18.2 percent) have been fastballs.

There's more. Howard doubled twice in Game 1. Both hits came against fastballs. His only other hit, a single in Game 4, also came on a fastball. Only one of his dozen strikeouts has been on a fastball, though. Clearly, the Yankees are committed to throwing Howard a steady diet of curves, sliders, cutters and sinkers.

The Phillies didn't work out yesterday, so what Howard thinks about all this must remain unknown.

Which is fine. All that matters is that, starting tonight, his bat will do the talking for him. Or not, as the case may be.

Daily News sports writer Marcus Hayes contributed to this story.