The 31-year-old was brought to the limelight almost two decades ago by Sarpong, who was then the coach of Accra Academy.
Although, the former Sunderland star has revealed plans to retire in 2019, Sarpong insists it must be now to save his legacy.
"Asamoah Gyan has done enough for Ghana and must call it a quit now. He said he'll quit in 2019 after the Afcon but I think it should be now because of his current situation," Sarpong told Goal.
"I've known him from his adolescent stages and although, he is mentally strong, the criticisms he is facing now because of his injuries are too serious.
"He should leave the stage while the applauses are high to save his legacy. Some people believe he is not paving ways for young talents to be nurtured because the coach can't overlook him," he said.
He added: "He should concentrate on club football and reduce the workload in him. I don't think his absence won't affect Ghana too much since Kwesi Appiah is in the process of rebuilding a formidable side to lift the 2019 Afcon title. The young strikers will gradually fill in his shoes."
Gyan has scored 51 goals in 105 appearances since 2003 but has hit the back of the net only twice since 2015.