Via Politico:

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.

Maybe he was tired of all the winning.