Michael Krull, who became campaign manager when most of Gingrich's staffers quit in June 2011, is also leaving, CNN reported. He is being replaced by Vince Haley, a longtime aide to Gingrich.
"The campaign is being redesigned to make it convention ready," spokesman R.C. Hammond told CNN. "Speaker Gingrich is committed to going all the way to Tampa."
Gingrich, a former U.S. House speaker from Georgia, was considered a non-contender until his poll numbers began rising after the departure of Herman Cain from the Republican primary field. Gingrich won the South Carolina primary but has since stalled.
Almost 60 percent of Republicans surveyed by CNN/ORC in a poll released Tuesday said Gingrich should end his candidacy.
Santorum, who called Gingrich a "good man," told CNN he wishes Gingrich well in future endeavors and said the Republican race is becoming more clearly one with two real contenders.
Hammond insisted Gingrich is in it for the long haul.
"We are going to invest in online, low-cost communications," Hammond said. "In many ways we will be talking directly to the delegates. The only way to beat Barack Obama is to have a distinct choice. Mitt Romney and Rick Santorum will lose to Barack Obama."