Career
After retiring, he became a manager. Born in Alnwick, Northumberland, England, Dreyer started his career with Wallingford, leaving to join Oxford United in January 1985. He joined Torquay United on loan in December 1985 and made his league debut, for Torquay, on 14 December in a 1–1 draw at home to Cambridge United.
He returned to Oxford on 13 January 1986, but moved on loan again on 27 March 1986, joining Fulham until the end of the season.
He broke into the Oxford first team the following season, playing 60 times before a £140,000 move to Luton Town on 27 June 1988. In six years at Kenilworth Road he played 214 games, scoring 13 times, but was released at the end of the 1993-1994 season.
In July 1994 he joined Stoke City, but started only two games for the Potters. He joined Bolton Wanderers in March 1995, and was part of the Trotters squad which secured promotion to the Premier League via the play-offs.
On 6 November 1996, he signed for Bradford City for £25,000.
He scored on his debut in a 3–3 draw at Huddersfield Town. They included two goals at Wycombe Wanderers and one in City"s 3–2 upset of Everton. Although Dreyer made just 14 starts in City"s season in the top flight, he made an equally vital contribution with the only goal in a 1–0 victory over Sunderland as Bradford stayed up by just two points.
He left the Bantams after turning down a new one-year contract as he felt he deserved a two-year deal.
He joined Cambridge United in July 2000, playing a major role in keeping Cambridge in Division Two the following season. He left after one season (and one goal against Colchester in the Football League Trophy) and was linked with a return to Oxford United as player-coach in July 2001.
Later that month he did join Oxford, but only on trial as a player, joining in with pre-season training and playing in a pre-season friendly. However, the Oxford board would not provide the money needed, claiming that they had no need for an extra defender, and on 4 August 2001 he signed for Conference side Stevenage Borough.
In January 2002 he was linked with a move back to the Football League with Torquay United, but remained with Stevenage.
He was caretaker manager of Stevenage for a spell in January 2003 alongside David Preece, but left in May 2003 to seek a managerial position. In May 2003, Dreyer became manager of Maidenhead United, guiding the team to the quarter-finals of the FA Trophy and securing a place in the new Conference South. However, Maidenhead struggled at the higher level and Dreyer left in November 2004.
In August 2005, Dreyer joined Long Melford as a player, whilst he was also working as assistant manager of Hemel Hempstead Town.
In December 2006, Dreyer was named as assistant manager of Rushden & Diamonds. On 2 May 2008, Dreyer was named assistant manager to Graham Westley at Stevenage Borough.
Dreyer followed Westley to Preston North End in January 2012, taking up the role of assistant manager. On 14 February 2013, Dreyer was named as Caretaker Manager of Preston North End following the departure of Graham Westley.