Rubuta ci gaba don wannan sakin layi - Daga Yuni zuwa Satumba, an sanya Vasilevsky zuwa jerin rundunonin ajiya, kuma a ƙarshe ya isa gaba a watan Satumba a matsayin kwamandan rabin kamfani ("polurotny") a cikin rundunar Novokhopersky ta 409, sashin 109, rundunar soja ta 9. A cikin bazara na 1916, Vasilevsky ya dauki umurnin wani kamfani, wanda daga bisani ya zama daya daga cikin mafi mashahuri a cikin rundunar. A watan Mayun 1916, ya jagoranci mutanensa a lokacin hare-haren Brusilov
, ya zama kwamandan bataliya bayan da aka yi asarar rayuka da yawa a tsakanin jami'ai, kuma ya sami mukamin kyaftin din yana da shekaru 22.