Johnson will join Hull for training on Thursday and will stay until November 9 ahead of a potential loan move.
The American international told Chicago's official website: "Going to Hull City will be a fantastic training opportunity.
"Going over every year has proven great for me. As a player, to get better every single day, to develop, to play at that level, to see how it's done day-in, day-out is great for myself.
"I think to get over there and showcase what you can do only does yourself good. Going right over there at the end of the season is going to be great for me as I'm not missing a beat."
Johnson, 25, was named Chicago's MVP and Defensive Player of the Year for 2014.