The headless statue of hunting goddess Artemis dates from the middle of the first century B.C., archaeologist Athanassios Tziafalias said.
The statue, standing 32 inches tall, was found July 4, during work on the fringe of the ancient theater at Larissa, a town about 225 miles north of Athens.
The figure, dressed in a short tunic and a deerskin, lacks its arms and lower legs.
Archaeologists also found about 60 limestone and marble sections of columns from the theater, together with more than 100 inscribed stones expected to shed light on the town's history, Tziafalias said.
But hopes are high that more significant finds could be among the fragments.
"There are many marble pieces wedged among the columns, which have not yet been investigated," a Culture Ministry press release said.
Tziafalias said the theater "has a lot more to give us."
Built in the 3rd century B.C., the building was destroyed by earthquake two centuries later. It was rebuilt by the Romans, who used the broken columns as the foundation for a large pavement.
"It is considered likely that this pavement was part of works to turn the theater into an arena where gladiators fought," the ministry announcement said.