The 19-year-old was a key member of the side that helped the Royal Blues finish the 2013/14 campaign strongly and qualify for the UEFA Champions League group stages for a third consecutive year.
He was rewarded for his impressive displays with a call-up to the senior Germany squad and made his full international debut in a 0-0 draw with Poland in May, but has since been plagued by muscular trouble in his left thigh. After months of struggling with the injury, club doctors have decided a low-impact rehabilitation programme to be the best way to facilitate Goretzka's long-term recovery.
"Leon has always handled himself in a professional manner so it's not an easy situation for him," said Schalke sporting director Horst Heldt. "The only thing that can help now is patience, and then here at Schalke we'll get the best of him again."