Miller, a first baseman, leads the big leagues with a .500 average and a 1.509 OPS.
"They all feel fine," Guardians manager Terry Francona said. "That's good, but it's frustrating."
Francona said each player reported symptoms and underwent tests Tuesday. They immediately entered health and safety protocols once the diagnosis was made.
First baseman Yu Chang, who was placed on the IL for undisclosed reasons on Friday, was confirmed by Francona to have tested positive for COVID-19.
"I don't know that we're out of the woods yet," Francona said. "I hope we are, but we don't know yet. Unfortunately, in a clubhouse, there is a lot of close contact."