Anthony Parker did nothing in his first few nba seasons, left for europe then came back to be a solid nba player.
Green is playing for an average Russian team.
Anthony Parker was Euroleague MVP, he was one of the top players in Europe before he came back.
Gerald Green is still only 25 years old.
Anthony Parker was 31 when he returned to the NBA.
If G.Green puts his head down and continues to work, there is still plenty of time for him to right his career and make it back to the NBA as a solid two-way role player. He's certainly not ready for that right now (at least evidenced by his previous summer league showing) ... but in a few years, possibly.
I think he's still too young to be written off completely ... although I fully concede that GG still has a long way to go before he is ready to be a useful NBA player (and that he may never reach that point).