A man walks outside an AutoZone store in Albuquerque, New Mexico.

AutoZone shares dropped 9.5 percent on Tuesday, erasing a sharp gain from earlier in the day, after worries of rising costs for the company were raised during its quarterly earnings call.

During the call, CEO William Rhodes said he expects selling, general and administrative expenses to rise between 6.5 and 7.5 percent for fiscal year 2019 as the company raises wages.

Those comments "would seem to [indicate] concerns about labor inflation and possible peak margin," Jefferies analyst Bret Jordan told CNBC in an email.