| Metin Mert | |
| Birth Name: | Detlef Müller |
| Birth Date: | 21 May 1965 |
| Birth Place: | Duisburg, West Germany |
| Height: | 1.80 m |
| Position: | Goalkeeper |
| Youthclubs1: | SV Wanheim 1900 |
| Youthclubs2: | Duisburger SV 1900 |
| Youthclubs3: | VfB Homberg |
| Youthyears4: | –1984 |
| Youthclubs4: | VfL Bochum |
| Years1: | 1983–1985 |
| Clubs1: | VfL Bochum II |
| Caps1: | 5 |
| Goals1: | 0 |
| Years2: | 1985–1988 |
| Clubs2: | Westfalia Herne |
| Years3: | 1988–1995[1] |
| Clubs3: | Sarıyer |
| Years4: | 1995–1997 |
| Clubs4: | Trabzonspor |
| Caps4: | 19 |
| Goals4: | 0 |
| Years5: | 1997–2002 |
| Clubs5: | Kocaelispor |
| Caps5: | 73 |
| Goals5: | 0 |
| Years6: | 2002–2003 |
| Clubs6: | Konyaspor |
| Caps6: | 34 |
| Goals6: | 0 |
| Years7: | 2003–2004 |
| Clubs7: | Antalyaspor |
| Caps7: | 14 |
| Goals7: | 0 |
| Goals8: | 0 |
| Manageryears1: | 2005–2006 |
| Managerclubs1: | Ankaragücü (assistant coach) |
| Manageryears2: | 2006–2008 |
| Managerclubs2: | Rizespor (goalkeeping coach) |
| Manageryears3: | 2008 |
| Managerclubs3: | Ankaraspor (goalkeeping coach) |
| Manageryears4: | 2008–2009 |
| Managerclubs4: | Malatyaspor (goalkeeping coach) |
| Manageryears5: | 2009–2010 |
| Managerclubs5: | Eyüpspor (goalkeeping coach) |
| Manageryears6: | 2010–2011 |
| Managerclubs6: | Denizlispor (goalkeeping coach) |
| Manageryears7: | 2011–2014 |
| Managerclubs7: | Akhisar (goalkeeping coach) |
| Manageryears8: | 2014– |
| Managerclubs8: | Galatasaray (goalkeeping coach) |
Metin Mert (born Detlef Müller; 21 May 1965) is a German-born naturalised Turkish professional footballer who played as a goalkeeper.
Detlef Müller was born Duisburg, West Germany. His first Oberliga game for Bochum II was on 31 December 1983 in a 3–0 win against Hammer SpVg. He was substituted on in the 75th minute for Markus Croonen. In summer 1985 Müller transferred to Westfalia Herne, where he played until 1988.
During a vacation to Turkey in 1988 Müller was spotted by Erdal Keser playing Beach soccer. He was offered a contract from Sarıyer out of the Turkish First Football League, which he accepted.
| Club | Season | League | Cup | Continental | Total | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Division | Apps | Goals | Apps | Goals | Apps | Goals | Apps | Goals | ||
| VfL Bochum II | 1983–84 | Oberliga Westfalen | 5 | 0 | — | — | 5 | 0 | ||
| 1984–85 | 0 | 0 | 0 | 0 | — | 0 | 0 | |||
| Total | 5 | 0 | 0 | 0 | 0 | 0 | 5 | 0 | ||
| Westfalia Herne | 1985–86 | Oberliga Westfalen | 27 | 0 | — | — | 27 | 0 | ||
| 1986–87 | — | — | ||||||||
| 1987–88 | — | — | ||||||||
| Total | !0 | 0 | 0 | 0 | ||||||
| Sarıyer | 1988–89 | 1.Lig | — | |||||||
| 1989–90 | — | |||||||||
| 1990–91 | 29 | 0 | 2 | 0 | — | 31 | 0 | |||
| 1991–92 | 22 | 0 | 1 | 0 | — | 23 | 0 | |||
| 1992–93 | 19 | 0 | 2 | 0 | — | 21 | 0 | |||
| 1993–94 | 25 | 0 | 2 | 0 | — | 27 | 0 | |||
| 1994–95 | 2.Lig | 20 | 0 | 3 | 0 | — | 23 | 0 | ||
| Total | ! | |||||||||
| Trabzonspor | 1995–96 | 1.Lig | 19 | 0 | 1 | 0 | 1 | 0 | 21 | 0 |
| 1996–97 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | ||
| Total | 19 | 0 | 1 | 0 | 1 | 0 | 21 | 0 | ||
| Kocaelispor | 1997–98 | 1.Lig | 11 | 0 | 2 | 0 | 0 | 0 | 13 | 0 |
| 1998–99 | 5 | 0 | 0 | 0 | — | 5 | 0 | |||
| 1999–2000 | 10 | 0 | 0 | 0 | ||||||
| 2000–01 | 28 | 0 | 3 | 0 | — | 31 | 0 | |||
| 2001–02 | Süper Lig | 19 | 0 | 4 | 0 | — | 23 | 0 | ||
| Total | 73 | 0 | 9 | 0 | ||||||
| Konyaspor | 2002–03 | 1.Lig | 34 | 0 | 2 | 0 | — | 36 | 0 | |
| Antalyaspor | 2003–04 | 1.Lig | 14 | 0 | 1 | 0 | — | 15 | 0 | |
| Career total | ! | |||||||||
Kocaelispor