[4] He made his debut for VfB Stuttgart in the Bundesliga on 29 November 2015 against Borussia Dortmund.

He scored his first official goal for the team on 22 August 2016 in a match against FC 08 Homburg for the DFB-Pokal.

On 28 March 2016, Bulgarian media reported that Borys had already spoken with BFU officials and had expressed his desire to represent Bulgaria.

[11] Petev once again confirmed that Tashchy will play for Bulgaria on 27 May 2016, but he couldn't join the team for the Kirin Cup due to paper problems.

[12] The process of finalizing his paperwork to play for Bulgaria was put to a halt after Petar Houbchev succeeded Petev as manager of the national side.