Some players who came from the Dominican Republic on an MLB chartered flight tested positive for COVID-19, causing other players on those flights to go into isolation.

Multiple players who took one of two Major League Baseball-chartered flights from the Dominican Republic to Miami on July 1 have since tested positive for the novel coronavirus, according to several people with knowledge of the situation. Players and staff members were not tested before boarding the planes, according to six people with knowledge of the travel logistics, lending more skepticism to baseball’s restart plan.

WashingtonPost.com

I don’t see much skepticism at the link, and less in the article.

Testing in the DR is difficult. So if MLB tested there, all the players would have been delayed. By bringing in the ones with no symptoms, the testing could be done quicker, with the caveat that players who traveled would need to isolate. So unless MLB got lucky and no one was positive, the players would either wait in the DR or wait in a hotel room. I rather have them in the US, ready to go when and if they are cleared.