“In the last seven days or so, I’ve seen movement towards Rubio and away from Cruz among conservatives that are not comfortable yet with the idea of Trump,” said Jamie Johnson, a long-time GOP operative in the state who worked on Rick Perry’s campaign this cycle.

Johnson predicted a victory for Trump in Iowa, who he believes will surpass the 30 percent threshold. But he said he expects Cruz and Rubio will run neck-and-neck past the 20 percent mark.

“I think he’s going to surge enough to worry Ted Cruz’s supporters,” Johnson said. “Conservatives that are worried about Trump getting the nomination are going to put the bat in Rubio’s hands here so he can go swing it in New Hampshire.”

There are signs of worry coming from the Cruz camp, which on Friday began shifting its negative advertising from Trump to Rubio, according to a report in The New York Times.

The move comes a day after Cruz had a shaky debate performance by his standards. The Texas Republican absorbed cutting attacks from his rivals, including Rubio, who chided him for his holier-than-thou approach.