The 23-year-old was dropped from the squad on Monday after failing to report to camp on the scheduled date for the medical team of the Black Stars to asses him.
Ayew picked up a hamstring injury while training at Olympic Marseille last week.
Coach Akwesi Appiah said he cannot include him in the squad since his planned day of arrival which is Wednesday is the deadline for the submission of the final list for the 2013 Afcon.
“I think it is a big blow, when I heard it, I was shocked," Lamptey told Goal.com Ghana.
“I think Kwesi Appiah has done his homework very well."
“I believe he spoke to the player and explained to him there was no time.
“Dede is a senior player in the team and his absence will be felt,” the 1991 Fifa Under-17 world cup gold medalist added.