The 23-year-old hasn’t played since hobbling through the second round replay victory over Harrogate Town on December 13 with a knee injury sustained in the original meeting between the clubs 12 days previously.
Speaking at the press conference on Wednesday evening, United player-manager Sean Ray said: “Matt’s doubtful for Saturday. We probably won’t know until Friday; we’re going to give Matt all the time he needs.”
With George Howard, who has been deputising for Armstrong-Ford in the recent league games, and fellow 18-year-old Joe Winchester the only other options from within the club, Ray has been looking to bring someone in from elsewhere by the deadline of 12noon today.
“We’re looking to bring someone else into the squad just in case,” continued Ray. “We’re speaking to another couple of clubs to try and bring a ‘keeper in. We know we can’t go into that sort of game with goalkeepers that aren’t experienced enough.”
Eastbourne-based Armstrong-Ford, the son of former United goalkeeper and top tennis umpire Gerry Armstrong, has made 50 appearances for United since joining from Horsham in October 2011 and kept nine clean sheets.
The likes of Zac Attwood, Lee Carey, Elliott Cox and Josh Jirbandey are expected to be okay, while Ian Daly, the 22-year-old attacking player from Bromley who made his debut against Lewes on New Year’s Day, is eligible. Jirbandey and Scott Manning are available despite their red cards over the past week.