Officials with Major League Baseball, the Marlins and Pirates expect the games to be played as scheduled May 30-31, they said Thursday. But the teams, MLB and the players union are continuing discussions about the trip.
"We recognize the importance of the trip," Marlins pitcher Craig Breslow said. "But at the same time, our health and the health of our families is paramount."
Major League Baseball commissioner Rob Manfred said the league is in contact with the union about the issue.
"We're having ongoing conversations with the union," he said.
The U.S. Centers for Disease Control and Prevention has said that Zika can cause a birth defect called microcephaly, where infants are born with unusually small heads. The virus is most often spread by mosquito bites, but it also can be spread through sexual intercourse.
Since the virus lasts longer in semen than it does in blood, the CDC advises abstaining or using condoms if a man is exposed while his partner is pregnant. It also can be tough to know if someone has contracted Zika, because some infected people do not show any symptoms.
Breslow also noted that CDC guidelines recommend that couples trying to get pregnant should wait six months if the man was diagnosed with Zika and was in an outbreak area.
"There are guys who are uncomfortable engaging in the lifestyle changes being recommended by the CDC," he said. "I'm not sure that's fair to ask of 20- to 30-year-old men who are potentially looking to start families or expand families."
U.S. health officials say Puerto Rico is the front lines of the nation's battle with Zika. While there has been no mosquito transmission of the virus in the continental United States, there have been hundreds of cases in the island territory.
As of last week, Puerto Rico had nearly 450 confirmed Zika illnesses, almost all of them infections that people got on the island. In comparison, there were 358 cases in the 50 states, and all of them were tied to travel abroad to Zika outbreak countries.