On-loan Lee Martin will be absent due to a ligament injury in the seven minutes he played in the first period against the Robins. Meanwhile Ugo Ehiogu will sit out against the southerners because of a calf injury.
Chris Morgan will also not feature due to suspension.
Blackwell said:"Everyone else is fit and raring to go and i don't have the slightest concern about who comes in and plays where. The players have handled that sort of problem whenever it has occurred, none more so than against Bristol City when we had to make three substitutions through injury during the game.
Blade player himself Chris Lucketti could play against United for Southampton. Blackwell finished commenting on the situation:"That will be resolved in the next couple of days and at the moment we are in negotiations with Southampton about something else."