The 2021 MLB All-Star selection was pulled from the contest after scoring on Josh Bell's three-run home run in the top of the first inning. Gerardo Parra replaced him in the Nationals' lineup.
The timeline for Turner's positive COVID-19 test result indicates his test was administered Monday.
Turner becomes the second prominent player to test positive for the coronavirus Tuesday. Earlier in the day, Milwaukee Brewers star Christian Yelich tested positive and is experiencing mild symptoms despite being vaccinated.
The Brewers placed Yelich on the COVID-19 injured list, and he must miss a minimum of 10 days.
The 28-year-old Turner has a .322 batting average with 18 home runs, 49 RBIs and 21 stolen bases this season. He has been mentioned in trade rumors ahead of Friday's trade deadline, as the Nationals -- entering Tuesday with a 45-54 record -- have fallen out of the playoff race.
Turner will now be out at least 10 days, which would extend beyond this week's trade deadline.
In 636 career games with the Nationals, Turner has a .300 batting average with 93 home runs, 306 RBIs and 192 stolen bases.