The midfielders loan was due to expire after Tuesday's game at Stevenage, but boss Ronnie Moore has secured a deal to keep Randall at Don Valley for a longer period.
The extended deal is through until the end of the season.
Randall is now fully fit after a behind closed doors game with Sheffield United in midweek. He initially broke his collarbone on his debut in October and was in hot water last week after a breach of club dicipline which was dealt with internally.
MillersMAD wish Mark all the best.