Early career Keller began his career in France playing for
Mulhouse. In 1991 he moved to
Strasbourg whom he helped win the
1995 UEFA Intertoto Cup, scoring a hat-trick in the second leg of the final against
FC Tirol Innsbruck. In 1996 he moved to Germany to play for
Karlsruher SC.
West Ham United Keller was signed by West Ham in July 1998 on a free transfer by manager
Harry Redknapp. He made his debut on 12 September in a 2–1 home win against
Liverpool as an 86th-minute substitute for
John Hartson, and scored his first goal on 22 November in a 2–0 away win against
Derby County. He played 22 games in his first season in all competitions scoring five goals as West Ham finished in fifth place in the
Premier League to qualify for the
Intertoto Cup. this being the second time Keller had won the tournament having also won it four years previously at Strasbourg. West Ham therefore qualified for the
UEFA Cup as one of the three winners of the competition for that season. Keller played in three of West Ham's four games in the UEFA Cup and 34 games with one goal in all competitions during the
2000–01 season. He played three games before returning to West Ham.
Blackburn Rovers In January 2001, Keller was allowed to leave on a free transfer to
Blackburn Rovers, Keller played only five games for Blackburn, two in the league and three in the
FA Cup, all as substitute appearances. His last game came on 7 March 2001, a 3–0 home win against
Bolton Wanderers, when he was a 73rd-minute substitute for
Damien Duff. It was his last game in professional football. ==International career==