He spent his formative years at St. Petersburg's famous Smena football academy before joining FC Spartak Tambov, a second division club.

After finishing this suspension, Sychev signed a five-year contract with Olympique de Marseille, rejecting an offer from Dynamo Kyiv.

His transfer played a role in manager Yuri Syomin's decision to change the starting formation from 5–3–2 to 4–2–3–1 or 4–4–1–1, which would help Sychev form a strong attacking partnership with team's primary playmaker and captain Dmitri Loskov.

However, in August 2005, he sustained an anterior cruciate ligament injury and was forced to miss the rest of the year, which saw Lokomotiv dropping points in the closing stages of the league and eventually losing the title to CSKA Moscow.

[8] In July 2013, after returning from Dinamo Minsk, Sychev moved to fellow Russian Premier League side Volga Nizhny Novgorod on a year-long loan deal.

[13] Sychev was selected to play for the Russian national team at the 2002 FIFA World Cup, where he became the youngest player to appear for the Soviet Union or Russia at 18 years and 222 days.

[15] On 30 January 2024, Sychev was appointed president of his hometown club Irtysh Omsk in the third-tier Russian Second League.

[18] Outside of sports, he plays the guitar and was seen rapping at the MTV Russia Music Awards ceremony in Moscow with national teammate Diniyar Bilyaletdinov.

[18] In 2007, Sychev received a degree from the Russian State University of Physical Education, Sport, Youth and Tourism.