TMZ Sports has obtained video of the Brooklyn Nets superstar all in Sunday on a game of pickup football with some guys at a high school in New Jersey ... where he seemed to be playing wide receiver and running routes, but not getting a look on this particular play.

We're told they were playing 4 on 4 here ... and this was actually a soccer field. So, not really a gridiron, per se, but at least we're getting a chance to see him out in public.

He's been seemingly reclusive of late -- taking to IG Live to try and explain his vaccine status and rationale -- this as he remains the focus of national media amid his stance to not get the jab ... and forfeit millions of dollars to be a "voice for the voiceless."

While we imagine his coaches and teammates won't be too happy seeing this -- Kyrie hasn't practiced/played with the Nets in a good long while now, due to the NY vaccine mandates -- at least they can take solace in the fact that he's staying active and somewhat in shape(?) for if/when he caves and decides to get back on the court at some point this season.

Then again ... maybe he never will. It looks like the Nets are prepared to move forward without Kyrie for now -- and they could very well trade him if he stays hunkered down like this.