He was selected in the first round of the
1997 NHL entry draft, 14th overall, by the
Edmonton Oilers. At the time he was the highest-drafted Swiss player in NHL history. Riesen was twice a member of Switzerland's World Junior team (1997, 1998) and a member of its World Championship team (1998). Riesen made his North American debut on the AHL's
Hamilton Bulldogs team in
1998–99. Riesen played three seasons in Hamilton with his best season being in 1999–00 when he registered 60 points (29G-31A). Riesen made his NHL debut in the
2000–01 season with the Oilers, playing in 12 games in what would be his only NHL season. On July 1, 2001, Riesen was traded from the Oilers, along with
Doug Weight, to the
St. Louis Blues for
Marty Reasoner,
Jochen Hecht and Jan Horacek. Riesen never played for the Blues, opting to head back to Switzerland for the 2001–02 season to rejoin HC Davos. In the 2006-07 season, Riesen was the top goal scorer in the NLA with 37 goals. ==Career statistics==