Here's a cabinet photo of the team circa 1906...the player third from left in the back row is George "Chief" Johnson who played with the Cincinnati Reds before jumping to the Federal League.
He is listed as "Standing Bear" in the Sporting News Guide
Unfortunately because most of the players on the Nebraska Indians team went by names that Green probably gave them, identifying players on these teams is very difficult especially because he did not mention in his writings their real names.
Here is his 1916 Zeenut card.
