He's offering himself as a new generation of leader, but Sen. Marco Rubio is still respecting an old presidential campaign tradition: courting caucus goers in the kickoff state of Iowa.

The Florida Republican will be in Iowa this weekend on his first trip to the state since he announced his 2016 presidential candidacy. Rubio's appearance at a candidate forum in suburban Des Moines on Saturday will be an introduction to many voters, who have not seen Rubio as much as many of his competitors this year.

"Right now he's an undefined commodity, but there's a lot of interest in him," said veteran Republican strategist Doug Gross. "He's new and he's fresh."

On Thursday, new polling numbers from Quinnipiac University showed Rubio leading all GOP hopefuls, including former Florida Gov. Jeb Bush. Some analysts attribute his surge to the bump other Republicans received when they made their candidacies official.

Still, Iowa Republicans said they were intrigued by Rubio, a 43-year-old Cuban-American who is arguing he can provide forward-looking leadership and pull together a broader coalition of support than his rivals. But they said he'll need to take time to woo supporters in this politically significant state if he wants a strong caucus showing.

Brent Siegrist, a Republican from Council Bluffs and former statehouse speaker, said Rubio "just needs to be here. People are interested."

On Saturday, Rubio will also meet privately with business leaders and lawmakers and plans to appear at an ice cream social hosted by Republican state Sen. Jack Whitver. Earlier this year, he did a book signing in suburban Des Moines, and he campaigned here last year for Sen. Joni Ernst and in 2012 for Mitt Romney's presidential campaign.

But many Republicans have not encountered him yet even as other hopefuls - Texas Sen. Ted Cruz, former Texas Gov. Rick Perry and former Pennsylvania Sen. Rick Santorum among them - have made frequent trips and gotten a head start on forming relationships with local activists and party leaders face to face.

Spokesman Alex Conant said Rubio expects to spend time campaigning in the state in the months ahead and "we recognize Iowans don't know much about him and want to get to know him."

Rubio is among nine confirmed speakers for the Saturday event sponsored by the conservative Iowa Faith and Freedom Coalition. Also scheduled to attend are: Kentucky Sen. Rand Paul, Cruz, Louisiana Gov. Bobby Jindal, Perry, Wisconsin Gov. Scott Walker, former Arkansas Gov. Mike Huckabee, Santorum and businesswoman Carly Fiorina. Former Florida Gov. Jeb Bush and New Jersey Gov. Chris Christie are not coming.

The event will draw people from the party's evangelical conservative wing, which has significant sway over the caucuses, and Rubio is expected to address social issues, immigration and foreign policy. He will need to show that he is a substantive candidate, said former Iowa Republican Party co-chairman David Oman, who has not backed anyone but is leaning toward Bush.

"He is a compelling and charismatic candidate," Oman said. "On the plus side for the senator, there's a yearning among Republicans for such a candidate. On the minus side, the other party and indeed the country fell for such a candidate in 2008 and that didn't work out so well." Rubio is running for the presidency as a first-term senator, as President Barack Obama did.

"The challenge for Senator Rubio is to stay true to himself and parlay gravitas while not overpromising," Oman said.

Information from the Associated Press was included in this report.