Donald Trump Says He's Been 'Childish,' Has Fall Back Plan The GOP front runner's once dominate lead in the polls has been shifting.

 -- With summer over, so might be the "Summer of Trump" -- and now the man himself appears to be accepting it might not be a kind Fall.

“This is going to be an ebb and flow, how can I continue to lead by such wide margins?,” Donald Trump told NBC’s “Today Show” this morning.

The GOP front-runner's once dominant lead in the polls has been shifting. A new Wall Street Journal/NBC News poll this week shows the real estate mogul now in a virtual tie with retired neurosurgeon Ben Carson, polling at 21 percent to Carson’s 20.

“I’m a practical person,” Trump said. "If I see things aren’t going well, like for instance there are people right now in the Republican party who are not doing well I don’t think it’s going to change for many of them, at some point you have to get out. Right now, I’m leading every poll I get the biggest crowds by far. I had 20,000 in Dallas I had 35,000 people in Mobile, Alabama, you know so far it’s looking good…So I will go and if for some reason I think it’s not going to work, I’ll go back to my business.”

It’s one of the first times the GOP hopeful has recognized his lead is not as strong as it once was.

Despite the fact he admitted his attacking other candidates can be “a little childish," Trump told CNN. "I’m responding to them, I’m a counter puncher.”

Meanwhile, Trump will once again settle a battle with Fox News this evening. Trump is scheduled to appear on “The O’Reilly Factor” after saying a week ago he felt the network had treated him unfairly.

The Trump campaign and Fox News both say the billionaire will be discussing his concerns over Fox News’ coverage of his campaign with Chairman Roger Ailes. A time for that meeting has not be selected.