The 21-year-old, who has hit the headlines with Grimsby Town this season after spending most of the campaign on loan at Blundell Park, is now ready to sign for The Blades.
Manager Neil Warnock signed Middlesbrough's Dean Windass on Wednesday and is now set to further add to his striking options with Kabba.
Kabba is talking terms with United and should pen a loan deal on Thursday.
The highly-rated striker will move to Bramall Lane for an initial month-long period but the move is with a view to a permanent transfer.
