The first glimmerings of FCC support for a possible merger of T-Mobile and Sprint came to light Thursday. 

Democrat FCC Commissioner Jessica Rosenworcel reportedly expressed worry in private meetings that the number three and four U.S. carriers might not be able to remain viable if they stay independent, according to report from the Wall Street Journal. 

The news comes as regulators continue to express reservations around any consolidation at the upper tiers of the wireless industry. 

An environment of skepticism, however, hasn't deterred Sprint from moving ahead with a bid for T-Mobile. Recent reports suggest Sprint has already lined up financing for a bid and could announce a deal by June

Meanwhile, reports earlier this week claimed T-Mobile and parent company Deutsche Telekom (DT) are requesting a more than $1 billion breakup fee should regulators block a potential merger.

DT, which owns 67 percent of T-Mobile, is requesting the lucrative safety as well as seeking assurances that the T-Mobile brand and some of its management team would remain in place following the deal, according to the Wall Street Journal.