Wisconsin Gov. Scott Walker, who has surged to the top of the potential GOP presidential field, said on "This Week" Sunday that he wouldn't rule out putting U.S. boots on the ground in Syria if he were the commander-in-chief.

"We have to be - go beyond just aggressive air strikes. We have to look at other surgical methods. And ultimately, we have to be prepared to put boots on the ground if that's what it takes," Walker told ABC News' Martha Raddatz this morning.

"I don't think that's an immediate plan. … I wouldn't rule anything out," Walker said. "I think when you have the lives of Americans at stake and our freedom loving allies anywhere in the world, we have to be prepared to do things that don't allow those measures, those attacks, those abuses to come to our shores."

Gov Scott Walker (R) Wisconsin on 'This Week'

Walker also said the United States should "aggressively" take the fight to ISIS to prevent a potential attack on the U.S.

"I think aggressively, we need to take the fight to ISIS and any other radical Islamic terrorist in and around the world, because it's not a matter of when they attempt an attack on American soil, or not if I should say, it's when, and we need leadership that says clearly, not only amongst the United States but amongst our allies, that we're willing to take appropriate action," he said.

After his well-received speech at the Iowa Freedom Summit last weekend, Walker has quickly moved to the front of the large potential GOP 2016 field.

A new Bloomberg Politics/Des Moines Register poll this weekend of likely 2016 Iowa caucus-goers showed Walker leading the field with 16 percent of the vote, followed by Sen. Rand Paul at 15 percent, and former Arkansas Gov. Mike Huckabee at 13 percent, after factoring in 2012 nominee Mitt Romney's decision not to run.

Asked if he was 99 percent sure he'd end up making a bid for the White House, Walker responded, "I don't know that I'd take the odds. I'll just tell you one thing. After three elections for governor in four years in a state that hasn't gone Republican since 1984 for president, I wouldn't bet against me on anything."

Walker also sought to contrast himself with Hillary Clinton, widely considered the likely favorite for the Democratic presidential nomination, pitching himself as a new face and a Washington outsider.

"[W]hat I've heard across the country, is that people want new, fresh leadership with big, bold ideas, and the courage to act on it," Walker said. "And if we're going to take on a name from the past, which is likely to be former Secretary of State Hillary Clinton, I think for the party we need a name from the future.

"I think former Secretary of State Clinton embodies all the things that we think of Washington," he said. "She lives here, she's worked here, she's been part of the Washington structure for years."

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