The defender-midfielder has informed Hoffenheim that he does not plan to renew his contract with the Bundesliga club and will be leaving at season's end.
"We fought since summer to keep Fabian," Hoffenheim coach Markus Gisdol said Thursday. "But he decided to leave us."
Johnson, who primarily plays as a left back or winger, has made 13 appearances (nine starts) for Hoffenheim this season. The 26-year-old figures to be a key part of the USA's World Cup squad this summer after starting nine qualifying matches.