Republican presidential candidate Donald Trump is beefing up his team and refocusing on New York following a period of unforced errors and tactical failures that have raised doubts about his campaign operation.

Trump’s campaign announced Thursday that veteran operative Paul Manafort would be taking on an expanded role in the campaign amid the increasing likelihood of a contested Republican convention.

The campaign statement said Trump would be “consolidating the functions related to the nomination process and assigning them” to Manafort, who last week was named convention manager. “In this capacity, Mr. Manafort will oversee, manage, and be responsible for all activities that pertain to Mr. Trump’s delegate process and the Cleveland convention,” it read.

While the statement stressed that Manafort will be “working closely” with Trump’s existing team, including campaign manager Corey Lewandowski, the wording nonetheless signals a less prominent role for Lewandowski, who has been a constant presence at his boss’s side throughout the campaign. It comes following several incidents, including an interaction between Lewandowski and a female reporter in Florida that led police to charge him with simple battery charge. Lewandowski says he’s innocent.

“The nomination process has reached a point that requires someone familiar with the complexities involved in the final stages,” Trump said in a statement, adding that the move would allow the rest of his team to focus on upcoming races and the general election.

The campaign says that it will continue to expand the team, with several new hires and promotions expected in the weeks ahead.

Trump’s unconventional campaign operation is known for being unusually small and insular, with a tight-knit handful of top aides who usually travel with the candidate. Among them are Lewandowski, spokeswoman Hope Hicks, deputy campaign manager Michael Glassner and social media director Dan Scavino.

There are no pollsters, no media consultants, and few outside policy advisers, with the candidate determining much of the messaging himself.

Manafort brings with him decades of experience, including work on conventions for Presidents Gerald Ford, Ronald Reagan and George H.W. Bush.

The move comes after a serious loss in Wisconsin, where Trump was badly beaten by rival Ted Cruz, helping to galvanize anti-Trump forces and increasing the likelihood that Trump will be unable to amass the 1,237 delegates needed to win the nomination before the summer’s national convention. Cruz’s team also continues to outmaneuver the billionaire businessman in the fight for delegates at local and state-wide conventions, lining up commitments that could give him an edge.

Members of Trump’s team have acknowledged they were late to the complicated delegate wooing process and are now working to catch up with the help of other recent hires, including several staffers from former rival Ben Carson’s campaign.

In the meantime, Trump is re-focusing his efforts on New York’s April 19 primary, where early opinion surveys show him with a commanding lead.

Following a packed homecoming rally on Long Island on Wednesday night, Trump’s team cleared his schedule, cancelling a planned trip to California — including a press conference that had been scheduled for Friday at noon at the Trump National Golf Club Los Angeles.

“Mr. Trump has rescheduled his California trip and will be campaigning in New York,” Trump spokeswoman Hope Hicks said in an email. “He looks forward to returning to California in the weeks ahead.”

Trump’s team had also been planning an event in Colorado Springs, Colorado, on Thursday and had been expected by local officials to make another appearance in that state Saturday to coincide with the state’s convention. But those trips were scrapped as Trump focuses on amassing as many delegates as possible in his home state.

Former New York City Mayor Rudy Giuliani also announced Thursday that he will be voting for Trump in the upcoming New York primary, though he did not offer a formal endorsement.

Ed Goeas, a researcher for the anti-Trump Our Principles PAC and top Republican strategist, said it made sense for Trump’s team to be shoring up its delegate operations, but said that would likely do little to improve polls that show Trump’s deep vulnerabilities heading into a general election.

“I think they’ve been so focused on the primary, they haven’t looked at the damage they’re doing,” he said.

A new Associated Press-GfK poll shows that seven in 10 people, including close to half of Republican voters, have an unfavorable view of Trump.

(AP)