White Sox catcher Welington Castillo will be suspended 80 games for violating the league's joint drug agreement, a source told ESPN's Jerry Crasnick.
The suspension will be announced Thursday.
It was not immediately clear what Castillo will be suspended for, but the source said it was not for a steroid.
Castillo, a 31-year-old from the Dominican Republic, is hitting .270 with six home runs and 15 RBIs for the White Sox this season. He was behind the plate for Wednesday night's home game against the Orioles.
It's the second notable MLB drug violation this month.