The Welsh club had already been handed an allocation of 4,000 tickets in the top tier of the Halliwell's Stand and after selling the lot will be given 1,200 tickets for the lower tier.
The extra tickets went on sale this morning at 10:00am to Swansea City fans priced at £15.00 adults and £5.00 concessions and will be able to purchase them until tomorrow at 6:00pm.
Any remaining tickets unsold will be sent back to Sheffield United and will go on 'pay on gate' basis.