Jordan Mickey.
Jackson has a small guarantee on his contract next season, and owing that $650k instead of being able to trade it away this summer could determine whether we have max free agent room, so it can't be Jackson.
Young has shown himself to be useful in a break-glass-in-case-of-emergency situation.
Gerald is in the same position as Young. He has his moments.
Mickey can't get off the bench still in his second year, and his contract his completely unguaranteed for next season, so he's easy to release without any future ramifications. He's not going to be on the team next year regardless.
Based on this explanation I change my vote to Mickey. I originally voted Jackson.
I originally voted Green, not because I think he should but because he is the most logical if they bring in Terrence Jones.
But given this description, I will change to Mickey.