According to Steve Turner, we can add a Green River demos album to the long list of Pearl Jam related material that we are waiting for (RNDM's second album, PJ20 boxed set, Chicago 2014 Bootleg, Eddie's Out of the Furnace demos, etc.). Hopefully, this is one we'll soon see. Here's Steve Turner's interview on PressureDrop.TV as transcribed by AlternativeNation:
“When Green River ended, I wanted [Mark] to play guitar, 1. because he’s a rad guitar player. The earliest Green River demos are finally coming out, where Mark actually plays guitar on a couple of tunes.”
Mark added, “Only one.”
Steve said, “Well it’s awesome anyway. And 2. I didn’t want him climbing all over the stacks.”