Question: Gwyn Williams recruited an English professional footballer who plays what position?

full_context: Document 1: Dennis Wise: Dennis Frank Wise (born 16 December 1966) is an English former football player and manager, and former Executive Director of Football at Newcastle United.
Document 2: Ron Vlaar: Ron Peter Vlaar (] ; born 16 February 1985) is a Dutch footballer who plays as a centre back for AZ Alkmaar in the Dutch Eredivisie, having returned to play at his first professional club. Vlaar is a regular at centre back for the Netherlands national team and has played for and captained both Feyenoord and Aston Villa.
Document 3: Gareth Southgate: Gareth Southgate (born 3 September 1970) is an English football manager and former player who played as a defender or as a midfielder. He is currently the manager of the England national team. He won the League Cup with both Aston Villa and Middlesbrough (in 1995–96 and 2003–04 respectively, and as captain), and captained Crystal Palace to win the First Division championship in 1993–94. He also reached an FA Cup and UEFA Cup final as a player, and made 57 appearances for the England national team, featuring in the 1998 FIFA World Cup and both the 1996 and 2000 European Championships. His playing career ended in May 2006 at the age of 35, and after more than 500 league appearances, he was subsequently appointed Middlesbrough manager. He served as manager of Middlesbrough from June 2006 until October 2009, then managed the England U21 team from 2013 to 2016, before becoming the England national team manager in 2016.
Document 4: John Terry: John George Terry (born 7 December 1980) is an English professional footballer who plays for and captains Championship club Aston Villa. He commonly plays as a centre-back. He was previously captain of Chelsea and the England national team.
Document 5: César Azpilicueta: César Azpilicueta Tanco (] ; born 28 August 1989) is a Spanish professional footballer who plays for Premier League club Chelsea and the Spain national team primarily as a full-back but also as a centre-back.
Document 6: William Gwynn: William Gwynn (1856 - 1 April 1897) was a Welsh international rugby union forward who played club rugby for Swansea and would later become secretary of the Welsh Rugby Union. Gwynn was an all-round sportsman and as well as his success on the rugby pitch he also player cricket for Swansea, of which he became vice-president, and Glamorgan. Gwynn had also played association football and had captained Battersea College XI through two undefeated seasons. He would later become a referee and would officiate the very first football game between Swansea Town and Cardiff City.
Document 7: Gwyn Williams (rugby): Gwyn Williams is a Welsh rugby union and professional rugby league footballer who played in the 1930s, playing club level rugby league (RU) for Cardiff RFC, and playing representative level rugby league (RL) for Wales, and at club level for Wigan, as a wing , Centre , or second-row , i.e. number 2 or 5, 3 or 4, or, 11 or 12, during the era of contested scrums.
Document 8: Tony Carr: Anthony Carr MBE (born 5 September 1950) is an English sports coach and former Director of Youth Development at the West Ham United football club's youth academy and is recognised as one of the most influential figures in English football. A former graduate of the academy himself, whose footballing career was cut short by injury, he joined the club's staff as a youth coach in 1973. Since then in his tenure as director, as of 2010, Carr is credited with producing talent which has earned an estimated £80 million in transfer fees for the club, while the 23-man England squad for the 2010 FIFA World Cup contained no less than seven players trained by Carr – Rio Ferdinand, Frank Lampard, Joe Cole, Michael Carrick, Jermain Defoe, Glen Johnson and John Terry.
Document 9: Gwyn Williams (football manager): Gwyn Williams is Leeds United's former Technical Director, and a former Chelsea chief scout who discovered John Terry and helped make a £14m profit on Tore André Flo for the London side.
Document 10: Eric Dier: Eric Jeremy Edgar Dier (born 15 January 1994) is an English professional footballer who plays for Premier League club Tottenham Hotspur and the England national team. A versatile defensive player, Dier has been deployed as a defensive midfielder, a centre-back and a right-back.
Document 11: Jan Vertonghen: Jan Bert Lieve Vertonghen (] ; born 24 April 1987) is a Belgian professional footballer who plays as a defender for English club Tottenham Hotspur and the Belgium national team. He is the third-captain for Spurs.
Document 12: Gary Cahill: Gary James Cahill ( born 19 December 1985) is an English professional footballer who plays as a centre back for Premier League club Chelsea and the England national team. Cahill is the captain of Chelsea and vice-captain of England.
Document 13: Jim Cassell: Jim Cassell is a former Youth Academy Director at Manchester City. He has been responsible for the development of players such as Shaun Wright-Phillips, Joey Barton, Stephen Ireland, Nedum Onuoha, Daniel Sturridge, Michael Johnson and Micah Richards and many others.
Document 14: Rio Ferdinand: Rio Gavin Ferdinand (born 7 November 1978) is an English former professional footballer who played as a centre-back, and current television pundit for BT Sport. He played 81 times for the England national football team between 1997 and 2011, and was a member of three FIFA World Cup squads. He is regarded by many to be one of England's greatest ever players and he is one of the most decorated English footballers of all time.
Document 15: History of Birmingham City F.C. (1965–present): Businessman Clifford Coombs took over as Birmingham chairman in 1965, and appointed Stan Cullis as manager. Cullis's attractive football took them to cup semi-finals, but league football needed a different approach. Successor Freddie Goodwin produced a team playing skilful, aggressive football that won promotion to the First Division as well as reaching an FA Cup semi-final. Two years later, the club raised money by selling Bob Latchford to Everton for a British record fee of £350,000, but without his goals the team struggled. In 1979, with relegation a certainty, the club sold Trevor Francis to Nottingham Forest, making him the first British player transferred for a fee of £1 million; Francis had scored 133 goals in 329 appearances over his nine years at Birmingham. Jim Smith took Birmingham back to the top tier, but a poor start to the 1981–82 season saw him replaced by Ron Saunders of league champions Aston Villa. The team still lacked goals, and were relegated in 1984. The last home game of the 1984–85 promotion season was marred by rioting and the death of a boy when a wall collapsed; the events formed part of the remit of the Popplewell inquiry into safety at sports grounds. Saunders quit after FA Cup defeat to non-League team Altrincham, staff were laid off, the training ground was sold, and by 1989 Birmingham were in the Third Division for the first time in their history.
ground_truth: centre-back