Players who wish to apply for a trial can e-mail under-21s joint manager Lewis Thorogood at lewis.thorogood@bufc.co.uk until Sunday July 12.
Any player who wishes to be considered must e-mail a footballing CV with detailed playing history to date.
Pre-season for the under-21s will commence mid-July and the first pre-season friendly will be against Horncastle Town in the John Rawdon Memorial Trophy.