"This has been a tough week to see so many of my teammates come down with this virus and see how quickly it spreads. After much deliberation and thought, I have made the difficult choice of opting out for the remainder of the 2020 season," Diaz wrote on Instagram.
"This has been a decision that I have discussed with my family, and I feel it's the best one for me and my overall well-being. I will deeply miss my teammates and competing on the field. I wish my brothers the best and look forward to taking the field again with them soon!"
The 24-year-old Puerto Rican is one of the few Marlins players to test negative for COVID-19, according to MLB Network's Jon Heyman. As of Friday, 18 Marlins players and two coaches had reportedly tested positive.
Diaz was one of the main pieces to arrive from the Milwaukee Brewers in the Christian Yelich trade in 2018. He's recorded two hits in two games this season.
It was reported Friday that MLB determined Marlins players did not follow league safety protocols during a preseason trip to Atlanta.