The private sector added 102,000 jobs in June, fewer than the 140,000 economists expected, according to the ADP national employment report released on Wednesday.

Why it matters: It's a rebound from the 27,000 added in May, but still suggests that Friday's government jobs release — which includes public sector jobs, while ADP does not —might come in soft amid concerns that the job market may be slowing.

"The job market continues to throttle back. Job growth has slowed sharply in recent months, as businesses have turned more cautious in their hiring," Mark Zandi, chief economist of Moody’s Analytics, which releases the report alongside ADP, said in a press release.

Go deeper: The U.S. jobs market is starting to worry economists