The former Republic of Ireland striker played around 40 games in the Steel City for the Blades during the 2000/01 season and teamed back up with Neil Warnock along with new physio Tony Daley not so long ago.David Kelly: Blades Number Two
"I feel very fortunate that I'm back here," Kelly told the club's official website. "I'm fresh from playing and that will help me with the lads, especially the ones I played with.
"I know that myself and Tony will have to fill the boots left by Kevin Blackwell and Dean Riddle - but we will do things our own way.
"I'm looking forward to working with Neil. He will be a big help to me and Stuart McCall has already helped me enormously."