Though he turned 20 in July, Miro Heiskanen was the Stars' best defenseman as a teenager during the 2018-'19 season. He takes care of his defensive responsibilities and has a stylish offensive game. Along with Dak Prescott, Luka Doncic and Jordan Spieth, Heiskanen helps make up a bumper crop of young, talented athletes who should thrill Dallas fans for decades.