Nick Markakis retires after 15 MLB seasons with Atlanta Braves, Baltimore Orioles - ESPN
MLB players who are opting out of the 2020 season - ESPN
List of MLB players who opted out of 2020 season and why
Nick Markakis returns to Braves in dramatic fashion weeks after choosing to opt out of 2020 season
Braves' Nick Markakis: Everyone on Astros 'deserves a beating
Nick Markakis opts out of the 2020 season with Braves
MLB players who are opting out of the 2020 season - ESPN
Braves 'ultimate pro' OF Nick Markakis opts out of season - The Washington Post
Nick Markakis announces retirement