A spokesman for Rick Santorum seemed to downplay expectations for Michigan's upcoming primary on February 28, saying on Monday the candidate plans to campaign in the state but recognizes Mitt Romney's deep Michigan roots.

"Michigan is an important state, but it's not the only state," Hogan Gidley, Santorum's national communications director, said on CNN's "Starting Point with Soledad O'Brien." "We'll fight for every vote we can, of course. But it's Romney's home state."

Romney, who won Michigan in the 2008 Republican primary and whose father once served as governor, has already invested heavily in ads in the state, along with a super PAC supporting his candidacy.

But recent polls show Santorum topping Romney in the Wolverine State, though Romney is not too far behind. The latest survey from the American Research Group on Friday showed Santorum with a five-point advantage over Romney.

"Romney's planted a flag there, and he's done commercials talking about how he's grown up there. So it's clear he thinks that that state is important to him," Gidley said. "So the pressure is squarely on Mitt Romney at this point."

Gidley also defended Santorum on accusations that the candidate was questioning Obama's Christian faith this weekend. The candidate stirred controversy when he said the president subscribes to a different faith than that found in the Bible.

But the former Pennsylvania senator on Sunday clarified his remarks, saying he was referring to Obama's ideology, particularly on energy and environmental issues.

"What Rick was talking about was that the president's ideology has turned into a theology of sorts," Gidley said.