Was Ukraine_Eneolithic I6561 a Proto-Indo-European?

It's certainly a valid question, simply because the remains of this individual (sampled by Mathieson et al. 2018, see here) are from a cemetery of the Sredny Stog culture, which, based on historical linguistics and archaeological data, has already been posited to have been a Proto-Indo-European (PIE) culture, that gave rise to the supposedly Late Proto-Indo-European (LPIE) Yamnaya culture, that