Rubuta ci gaba don wannan sakin layi - Bayan Operation Barbarossa, mamayewar Jamus ta Tarayyar Soviet, ta fara a ranar 22 ga Yuni, 1941, Yermolkin ya yi yaƙi a yankin Kudu maso Yamma tare da rukunin sa. A matsayin wani ɓangare na Rundunar Sojoji ta 26, sashen da rundunarsa sun fara yakin a yankin Drogobych. A lokacin Border Battles a ranar 25 ga Yuni 1941 a matsayin wani ɓangare na sashin ya kaddamar da wani counterattack
a yankin Brody da Dubno, sannan a cikin mummunan fada ya koma baya zuwa Proskurov da Vinnytsia. Sa'an nan-Major Yermolkin ya ji rauni ta hanyar shrapnel a lokacin fada a yankin Radzivilov a ranar 28 ga Yuni. A watan Agusta a lokacin yakin Kiev an nada shi kwamandan rundunar bindigogi ta 300 na rundunar 7th Motorized, yana jagorantar ta cikin mummunar fada a kudancin Kiev a matsayin wani ɓangare na rundunar soja ta 26. An kama Yermolkin a cikin kewaye a watan Satumba amma ya sami damar komawa ga layin Soviet a watan Oktoba, bayan haka ya karbi umurnin Rundunar 'yan bindiga ta 680 na rukunin' yan bindiga na 169, wanda ke cikin manyan fadace-fadace a matsayin wani ɓangare na rundunar soja ta 38 na Kudu maso Yammacin yankin Volchansk. Daga Disamba ya umurci Rundunar 'Yan bindiga ta 584 na rukunin' yan bindiga na 199 na sojojin. A watan Yulin 1942 Yermolkin ya zama mataimakin kwamandan rundunar bindigogi ta 304 na rundunar a lokacin aikin kare Donbass.