It was mentioned by DeKay in July that byali was disgruntled and looking to leave after the Major, so this doesn't come as much of a surprise.
In the announcement that was released on the Virtus.pro website
Byali joined the team all the way back at the beginning of 2014 when the organization picked up the Polish roster. In his four and a half years with the team, the team received plenty of success in premier events including a victory at EMS One Katowice 2014, the team's only Major victory.
Virtus.pro has been on an extreme decline as of late and has almost completely reformed the roster that brought incredible success to the organization. With the recent additions of Michal "MICHU" Muller and Michal "snatchie" Rudski, byali is the third player to leave the team this year.
Photo courtesy of Adela Sznajder/DreamHack