Republican presidential candidates face a blank slate with Iowa voters heading into the 2012 cycle, Sen. Chuck Grassley (R-Iowa) said Thursday.

Grassley, the long-serving dean of Iowa's congressional delegation, said it's a "whole new ballgame" in the Hawkeye State, which plays host to the first-in-the-nation nominating contest for president.

The candidates who performed well in 2008 — former Arkansas Gov. Mike Huckabee (R) and former Massachusetts Gov. Mitt Romney (R), who finished first and second, respectively — shouldn't expect to duplicate their performances again, said Grassley.

"At this point if your question is based on who was involved in 2008 and who did well in 2008, I think you'd better forget that," Grassley told the conservative website Newsmax. "It's a whole new ballgame."

A slew of GOP candidates have already visited Iowa with an eye toward a run to challenge President Obama in 2012. Romney, Huckabee, Minnesota Gov. Tim Pawlenty, former Alaska Gov. Sarah Palin, Mississippi Gov. Haley Barbour, former Speaker Newt Gingrich (Ga.), Rep. Mike Pence (Ind.) and former Sen. Rick Santorum (Pa.) have all visited the state.

A CNN poll released last week found Huckabee had a slight edge. Twenty-one percent of Republican Iowa voters said they preferred the former Arkansas governor, while 20 percent backed Romney, 14 percent supported Palin and 12 percent would vote for Gingrich.

Grassley said it's too soon to tell which candidate has an edge, though.

"I think you have to look at what the situation is, maybe, six months from now to know who's got a hold — or, let's put it this way — who is gaining some ground in Iowa," he said. "I don't think you can conclude that anybody who did well last year is automatically going to do well this year."