Donald Trump is adding Chris Christie’s former campaign manager to his expanding team.

The GOP front-runner’s campaign announced Monday that it has hired Ken McKay to serve as a senior adviser to its delegate operations team.

McKay previously managed the New Jersey governor’s presidential campaign. Christie has since become one of Trump’s most prominent endorsers.

The hire comes as part of Trump’s major campaign staff overhaul over the last few weeks. Trump is trying to stave off an effort by his rivals to prevent him from amassing the delegates needed to win the nomination on the first ballot at the national convention. He’s also brought on Rick Wiley, who managed former rival Scott Walker’s campaign, and several former aides to Ben Carson. McKay has also held roles with the Republican National Committee and Republican Governors Association.

(AP)