[2] A product of the youth academy of Slavia Sofia, Vasilev was loaned out to Yantra Gabrovo in January 2016.
He made his debut for the team on 8 August 2016 in a league match against Ludogorets Razgrad II keeping a clean sheet.
[6] He completed his professional First League debut on 30 July 2017 in match against Levski Sofia.
[8] In July 2020, Vassilev joined Beroe Stara Zagora.
[9] Vasilev made his debut for Bulgaria U21 on 8 June 2017 in a friendly match against Georgia U21.