Heyward has been hampered by a deep bone bruise on his left thumb for nearly two months.
Heyward, who was voted to start for the National League by fans, had a cast removed from his hand on July 4 and said he had hoped to participate in the Midsummer Classic.
That came less than a week after Heyward admitted he wouldn't try to play in the game.
Buster Olney is a senior MLB writer for ESPN The Magazine. The Associated Press contributed to this report.