Vander Horst suffered a slight stroke in January 1973 and placed jurisdiction over the Diocese in the hands of the then coadjutor, Bishop William Evan Sanders, for the ensuing year, after which he returned to full activity.

[1] It was during Vander Horst's tenure that the organization of the Tennessee diocese, then a statewide body, expanded to three offices, one apiece in each region of the state, mainly due to growth in parishes and missions that began during the episcopate of Edmund P. Dandridge and continued under Bishop Barth.

Coadjutor Sanders opened a location in Knoxville to attend to churches in the eastern third of Tennessee, and beginning in 1966, W. Fred Gates, Jr., a bishop suffragan, maintained offices on the close of Memphis' St. Mary's Cathedral (the former statewide headquarters), to provide services and administration for those in the western third of the state, west of the Tennessee River.

This arrangement was devised because Vander Horst did not wish during his tenure to see the Diocese legally divided, as had happened in several nearby Southern states.

Also, the Nashville office closed after Vander Horst stepped down (the Diocese opted not to elect another suffragan to staff it), and did not reopen until the division was completed, albeit in a different location.