The 20-year-old joined the Glovers from Liverpool just six months ago following a loan spell at Huish Park.
However, Johnson now expects the youngster to be playing his football elsewhere next season.
"His future lies away from here," he told BBC Sport. "We feel he won't be in our squad so we need to help him find somewhere to play some football."
Yeovil play their first match of the League One season on August 9 when they entertain Doncaster Rovers.