So I think I may have been wrong about that in the OP (I have since corrected it). It looks like the player will remain in PS eligibility even while "elevated" for a game. So I think he can still be poached
From the CBA Article 33 Section 5:
https://nflpaweb.blob.core.windows.net/media/Default/NFLPA/CBA2020/NFL-NFLPA_CBA_March_5_2020.pdf