Question: Which Welsh professional footballer succeeded Kevin Blackwell to play for Sheffield United?

Context paragraphs:
Charlie Wilkinson (footballer): Charles Edward "Charlie" Wilkinson (7 May 1907 – 1975) was an English professional footballer who played as a full back for Leeds United, Sheffield United and Southampton in the 1930s.  He was a member of Sheffield United's FA Cup team that reached the final in 1936, where they were defeated by Arsenal.

2010–11 Sheffield United F.C. season: The 2010-11 season was Sheffield United's third consecutive season in the Football League Championship after coming 8th in the 2009–10 season.  It was Kevin Blackwell's third season in charge of United; however, he left Bramall Lane in mid-August after losing at home to QPR.  Gary Speed was named as his successor but lasted only until December when he left to take over the Wales national side.  Following a short spell as caretaker by John Carver, Micky Adams was appointed manager for the rest of the season.  It was a turbulent season off the pitch and results declined, with Adams being unable to save the team from relegation to League One for the first time in 23 years.

William Egan (footballer): Thomas William Egan (1872–1946) was a Welsh professional association footballer who played as an inside forward.  Egan played in the Football League for Ardwick, Burnley, Sheffield United and Lincoln City.  He was awarded one cap for the Wales national football team for the match against Scotland on 26 March 1892.

Bramall Lane: Bramall Lane is a football stadium in Sheffield, South Yorkshire, England.  It is the home of Sheffield United.  As the largest stadium in Sheffield during the 19th century it hosted most of the city's most significant matches including the final of the world's first football tournament, first floodlit match and several matches between the Sheffield and London Football Associations that led to the unification of their respective rules.  It was also used by Sheffield Wednesday and Sheffield F.C. for major matches.  It has been the home of Sheffield United since the club's establishment in 1889.  It is the oldest major stadium in the world still to be hosting professional association football matches.

Jack Jones (footballer, born 1869): John Leonard "Jack" Jones (1869 – 24 November 1931) was a Welsh professional footballer and amateur cricketer.  He played football for Bootle, Stockton, Grimsby Town, Sheffield United, Tottenham Hotspur, Watford and Worcester City.  Jones also played cricket for Stockton Cricket Club and Sheffield United Cricket Club.  Born in Rhuddlan, he represented Wales on 21 occasions.

Ernest Blackwell: Ernest Blackwell (19 July 1894 – 16 October 1964) was a footballer who played as a goalkeeper, spending the majority of his career at his hometown club of Sheffield United.  Born in Sheffield he was the cousin of England keeper Sam Hardy and brother of Aberdeen keeper Harry Blackwell.

Nick Blackman: Nicholas Alexander Blackman (born 11 November 1989) is an English professional footballer who plays as a striker for Maccabi Tel Aviv.  He can also play as a Winger.  Born in Salford, he started his career at Macclesfield Town before moving to Premier League club Blackburn Rovers.  After 3 years at Blackburn Rovers he was sold to Sheffield United for an undisclosed sum.  After scoring 11 goals in 6 months at Sheffield United, he signed a 3 ⁄ -year contract with then-Premier League club Reading.  He has also spent time on loan at Blackpool, Oldham Athletic, Motherwell and Aberdeen.

Len Allchurch: Leonard Allchurch (12 September 1933 – 16 November 2016) was a Welsh professional footballer.  Allchurch played in the Football League for almost twenty years, playing in the top flight with Sheffield United and having lengthy spells with Swansea City and Stockport County.  A Welsh international, he was born in Swansea and was the brother of the late Ivor Allchurch.  He had the distinction of never receiving a booking or a caution throughout his entire Football League career.

Gary Speed: Gary Andrew Speed, MBE (8 September 1969 – 27 November 2011) was a Welsh professional footballer and manager.

Stan Machent: Stanley Charles "Stan" Machent (23 March 1921 – 17 December 2012) was an English professional footballer who played as an inside forward in the Football League for Sheffield United and Chesterfield and in non-League football for Buxton and Hereford United. <ref name="CHESTERFIELD : 1946/47 - 2013/14"> </ref><ref name="SHEFFIELD UNITED : 1946/47 - 2013/14"> </ref>

Supporting paragraphs: 2010–11 Sheffield United F.C. season Gary Speed
Answer: Gary Speed