Chicago ? Conspiracy theories about the “fly factor” of baseballs are a big hit, so to speak.

With balls flying out of parks at an early season pace not seen since the suspicious heyday of 2001, the theory goes that Major League Baseball needed to do something to increase fan interest. And with steroids now banned, the next logical reason for the rise in power is juiced-up balls. Right?

“Maybe the ball is on steroids,” Cubs manager Dusty Baker said.

He was joking.

“I think stuff like that is so stupid,” said Cincinnati slugger Adam Dunn, who wasn’t joking.

But Dunn has helped the theorists with their argument because as of Saturday he had hit five home runs in ten games.

During the first week of the season, home runs were up 10.6 percent over last year. Detroit’s Chris Shelton has seven already. In fact, the ball seems to be flying out of Detroit’s historically stingy Comerica Park for the Tigers and White Sox.

But a day after the Reds hit those six homers against the Cubs, it was hard to find anyone buying into a secret stash of juiced-up spheres. And that includes Cincinnati pitcher Bronson Arroyo, who has a homer in each of his two starts, which puts him on a pace for 32 this season.

“I don’t see any difference in the ball, not at all,” Arroyo said.

He should know because, after all, he also throws the baseball.

Glendon Rusch, who allowed both of Arroyo’s home runs and was pummeled for four long balls Tuesday, agreed.

“I haven’t noticed any difference,” Rusch said.

“I don’t see any difference,” Baker said, serious this time.

Then why was the ball flying out on Wrigley’s wind Tuesday, and why were the Reds and Tigers leading their leagues in homers?

“I don’t think I’ve ever been to Chicago in April with the wind blowing out like this,” Dunn said. “We have a good hitters’ park (in Cincinnati). And our team is going to hit home runs whether we’re in our ballpark or Yellowstone Park. Our team is built for home runs.”

Dunn is correct about Chicago’s weather, with temperatures well above normal for this time of year. And as Wrigley watchers know, warm weather brings southwest winds, which beget home runs.

But the got-to-have-a-reason conspiracy theorists still believe something funny is going on. How else to explain Michael Barrett hitting two of his three homers when the wind was blowing in? Ditto for Derrek Lee?

“I don’t think the baseball was ever changed,” said Barrett, who handles lots of baseballs as catcher. “It’s hard for me to believe they could change the baseball to increase home runs. They’re so conscious about length of games. If they really juiced the ball, it would really increase the length of the games. They want fans to be happy, but they also want fans not to have those long, drawn-out games.

“In the course of the season, we’ll be able to tell a little bit better. As for me, personally, I’ve had (fast) starts like this before. Was the ball juiced then? I don’t think so.”

The Reds’ Ken Griffey Jr. hit a monster homer off Rusch on Tuesday, but that’s not unusual for Griffey.

“No different,” he said of the ball. “It’s just one of those wild weeks. Pitchers are ahead of hitters, and then hitters catch up, and two weeks from now everything will be even until August, when the bats get heavy.”

Cincinnati manager Jerry Narron, who also managed in the cozy confines of Texas, has his own theory: “I know if a pitcher elevates the ball to a hitter, (the hitter) has a chance to hit it out, no matter the size of the ballpark.”

Baker concurred. “You throw the ball hard down the (middle of the) plate,” he said, “they’re going to go out of the ballpark.”

Narron and Baker most likely are correct, because while the Cubs’ Rusch and Will Ohman allowed six homers – one short of the Cubs’ all-time record – Arroyo gave up none in seven innings on the same day. And Wednesday’s starters, Greg Maddux and Brandon Claussen, allowed only one ball onto the warning track in a combined 11 innings, with the wind out of the west at 15 mph.

Dunn says if anyone wants to see home runs decline in Wrigley Field, “the wind better hurry up and blow in, because it’s only going to get hotter here.”