Jim Murphy, Donald Trump’s national political director, is no longer playing an active role on the campaign, according to three sources briefed on the move – a troubling development for the Republican nominee coming just 19 days before the election.

"I have not resigned but for personal reasons have had to take a step back from the campaign," Murphy said in a statement to POLITICO. He did not elaborate on the reasons for his departure.

Several Trump aides said that Murphy has been conspicuously absent in recent days as the campaign mobilizes for the final push.

Since joining the Trump campaign in June, Murphy, a longtime party operative, has played a key role in setting up field programs in battleground states. He has emerged as a central point person between top Trump campaign officials and the Republican National Committee. Murphy also helped to oversee floor operations at the Republican National Convention in July.