Lucketti, 34 has initially signed on loan until the end of the season to cover for the injured Leigh Bromby but is expected to sign for United in the summer for a believed £300,000 fee.
Bromby is out for the rest of the season and will need to undergo an operation with knee ligament damage he sustained during the 0-0 draw with Crewe Alexandra last Friday night.
6ft tall Defender Chris Lucketti, who will wear the number 44 shirt is expected to make his full debut in Sarurday's trip to the Ricoh Arena, home of Coventry City FC.
"I have chased him for a long time and we have not got just a player, but someone I regard as one of the best professionals I have ever been involved with." Blades boss Neil Warnock told sufc.co.uk.
"With Leigh Bromby's absence being a massive blow to us, Chris's involvement here couldn't have come at a better time. He knows he will have to fight for his place but he's never been a shirker."
"I am always on the lookout for leaders and they don't come much bigger than Chris. He's a no nonsense centre-half and, though he is limited in some departments, I think that can be said about anybody.
"Chris wants another season, I know what he can do and we'll see what happens at the end of the season."