The news came out this morning.
The Cubs put Welington Castillo on the disabled list June 3 with a rib cage injury. He played a full nine innings the past two nights in Iowa, going 3 for 8 with two walks. He obviously felt fine afterwards, so the Cubs put him back on the active roster.
The veteran catcher Eli Whiteside played in eight games in Castillo's absence. He went 3 for 25 with a double and two RBI.
It seems likely that Whiteside will clear waivers and report back to Iowa.