The Pilgrims travel to face Southern League Premier Central promotion chasers Coalville Town (kick-off 3.00pm).
It will be the first-ever competitive meeting between the sides, although United have visited Owen Street twice in the last six seasons for pre-season friendlies.
The Ravens, who were pipped to the title on goal difference by Tamworth last season before losing on penalties to Rushall Olympic in the play-offs, have defeated Royston Town and Alvechurch on the road in the competition so far this season.
Coalville boast a strong ex-United contingent, including assistant manager Danny Davidson and players Andi Thanoj and Herve Pepe-Ngoma.
Michael Bostwick and Jordan Richards are both back in contention for the Pilgrims after suspension.
Should Saturday's tie remain level after 90 minutes, the match will be decided on penalties.
BBC Radio Lincolnshire full-match commentary, courtesy of Dave Remnant and Craig Singleton, is available.
Twitter updates will be available via @bostonunited throughout the afternoon.
Away supporters can purchase tickets here.
United will be wearing all amber.
PIC: Chris Bray.