WASHINGTON — In the latest sign of difficulty for his presidential bid, Senator McCain is cutting some staff positions from his campaign as part of a restructuring effort that follows a disappointing start in fund raising.

The campaign would not say how many reductions are taking place, but the changes do not involve senior aides to the Arizona Republican. The total campaign operation now numbers more than 120 people, and an aide emphasized that the cuts would not hit key political and communications operations. The shifts also include restructuring consultant contracts.

“A campaign is like any business. It’s dynamic,” a spokesman, Danny Diaz, said yesterday. “The McCain campaign is taking necessary steps to make sure we are as effective and efficient as possible.”

The moves come as the campaign is preparing to file its first-quarter financial disclosure statement to the Federal Election Commission this weekend, a report that is expected to show Mr. McCain with less money available than either of his two top Republican rivals, Mayor Giuliani and a former Massachusetts governor, Mitt Romney.

In fund-raising totals announced last week, Mr. McCain came in third with $12.5 million, despite entering the race as a front-runner for the nomination. Mr. Giuliani reported raising about $15 million, while Mr. Romney led all GOP hopefuls with $23 million, which included a $2.35 million personal loan.

Top advisers to Mr. McCain acknowledged that the total was less than they had hope for and soon announced plans to reorganize the campaign. Mr. Diaz said the staff moves occurring now were part of that plan.

The campaign’s fund-raising struggles have not helped Mr. McCain’s standing in the polls. A new Los Angeles Times-Bloomberg poll shows him dropping to third place in the Republican field, behind Mr. Giuliani and a former Tennessee senator, Fred Thompson, who has not even entered the White House race. Mr. Giuliani led with 29% of probable GOP primary voters nationwide, followed by Mr. Thompson with 15% and Mr. McCain with 12%. Mr. Romney, whose strength in fund raising has yet to translate into higher national poll numbers, was fourth with 8%.

The survey of 437 Republicans, with a margin of error of plus or minus 5%, was taken before Mr. Thompson disclosed Wednesday that he had lymphoma that was in remission. The disclosure was seen in political circles as an indication that the “Law & Order” star was serious about mounting a presidential bid.

The poll also served as notice that should he run, Mr. Thompson would almost certainly enter the top tier of candidates, surpassing conservative contenders such as Senator Brownback of Kansas and a former Arkansas governor, Michael Huckabee, who have struggled to gain traction in fund raising and in opinion polls. That could put even more pressure on Mr. McCain, making it more difficult for him to jump-start his campaign.

Yet while Mr. McCain has surely lost his front-runner status, he can take some comfort in recent GOP history. In 1996, Bob Dole was a party favorite who ran into difficulty before ultimately capturing the nomination. And in 2000, the establishment pick was President Bush, who overcame an inspired challenge from Mr. McCain himself to win the nod.