Nigel Adkins has made his first move in the transfer market with Martyn Woolford arriving at Bramall Lane.
The 29-year-old, an experienced Championship operator, formerly of Scunthorpe United, Bristol City and most recently Millwall, joins United on a two-year contract, with the option of a third.
The Pontefract-born frontman made 38 second tier appearances for the Lions last season and Woolford is no stranger to Adkins and his coaching staff, with the player having worked with the Blades boss during their time together at Glanford Park.
On adding a player he knows well to his squad, Adkins remarked: "We signed Martyn at Scunthorpe and he scored the winning goal at Wembley to win us promotion from League One.
"We are very aware of the talents Martyn brings to Bramall Lane. He can play in several attacking positions, is fit, strong, robust, honest, hard-working and has a fantastic professional attitude. He has been consistently available for selection over many seasons and knows the demands required of this level."
Woolford began his career in the Northern Counties East League, spending three seasons with Glasshoughton Welfare, prior to impressing during a term with Frickley Athletic in 2005/06. The England C international then joined York City for a five-figure fee in August 2006 and scored 23 times in 74 league starts during his two-year stint at Bootham Crescent.
Woolford and Adkins linked up for the first time in August 2008 with the winger penning a three-year deal at Glanford Park. In the 2009 League One play-off final at Wembley, he scored one and claimed two assists as Scunthorpe beat Millwall 3-2 to win promotion to the Championship.
In January 2011, Bristol City paid an undisclosed fee for Woolford's services in the Championship, prior to him signing for Millwall under Ian Holloway during the January transfer window in 2013.
Woolford, is excited by the challenge at Bramall Lane and remarked: "Being a Yorkshireman I know how big this Club is and I'm looking forward to getting started with the lads. It is great to be working with Nigel Adkins once again and everyone knows what the major goal is."