Leroy Towns, who had been the executive campaign manager for Sen. Pat Roberts (R-Kan.) has vacated that position, two Republicans familiar with the move told The Washington Post on Thursday.

The personnel shift is the latest sign that the Roberts campaign is quickly undergoing significant changes as it seeks to remake itself amid concerns from national Republicans. The National Republican Senatorial Committee has dispatched veteran strategist Chris LaCivita to serve as a senior adviser to Roberts. LaCivita will be in Kansas this weekend.

Towns did not respond to calls and emails seeking comment.

Towns has been a confidant of Roberts and a top aide for decades. From 1980 to 2001, he served as Roberts's chief of staff, first in the House of Representatives and later in the Senate. He also worked as a political director for the senator's campaigns. He began his career as a newspaper reporter.

After the primary, Towns unwittingly highlighted the residency questions plaguing Roberts when he told a local paper that the senator had gone "back home for two days or three to rest” -- by which he meant the Washington suburbs.

Polls show the senator's approval rating is strikingly low for an incumbent. He faces a potentially strong challenge from Greg Orman, an independent candidate who has not said which party he would caucus with in the Senate.

The first general election debate is Saturday.