Doctors have told Hall of Fame catcher Gary Carter that the tumors found on his brain likely are malignant, according to news reports.
The tumors were diagnosed last Saturday after the former New York Mets star began experiencing headaches and forgetfulness.
Doctors at Duke Medical Center told the 57-year-old Carter that they are "90 percent certain" the tumors are malignant, according to a report on the New York Daily News website.
"It was very hard for all of us to hear, as we have been hoping and praying that the tumors would be benign," one of Carter's daughters wrote on the family's website. "Lots of tears have been shed in the hospital room today, and we are all a bit scared of the unknown."
Carter won't know the official diagnosis until next week, according to the report Friday on NYDailyNews.com.
At the time of the initial diagnosis, Carter said, "my wife, Sandy, and our children and family thank you for your thoughts and prayers. We ask that you please respect our privacy as we learn more about my medical condition."
According to the website, the plan is for Carter to begin chemotherapy and radiation.
Carter, an 11-time all-star, retired in 1992 after a 19-year career with the Expos, Mets, Giants, and Dodgers. He was inducted into the Baseball Hall of Fame in 2003.