Tom Koehler says the Miami Marlins attended a seminar on the Zika virus that heightened concerns about playing two games in Puerto Rico against the Pittsburgh Pirates on May 30-31.

A decision is expected by the end of the week regarding whether the games will be played as scheduled or moved.

The U.S. Centers for Disease Control and Prevention gave a presentation on the disease to the Marlins and representatives of Major League Baseball and the players' union.

"The information was more shocking to both sides," Koehler said. "Maybe shocking isn't the correct word, but there was a lot more information and data and numbers thrown our way that we didn't have."