The FCC may need to approve a Sprint/T-Mobile merger. But not yet.

One of the major hurdles facing Sprint right now is whether federal regulators would even approve a T-Mobile merger.

Back in 2011, the Federal Communications Commission rejected AT&T's own bid to buy out T-Mobile over concerns that it would put too much power in the hands of the country's strongest phone companies. A deal involving Sprint would be a little different, and it's been cited as one reason why the FCC might change its tune this time. But observers say that even with a new chairman at the agency's helm, the government still isn't likely to smile on a deal right away.

"No one's in a distressed situation right now," says telecom analyst Jeffrey Silva. "They may want to see how T-Mobile and Sprint fare, having improved themselves on a number of levels recently." But that could change in the future, Silva adds, particularly if either company winds up faltering. If T-Mobile fails to win subscribers, regulators could see it as evidence that the market can only reasonably support three major carriers. There are barely more wireless subscriptions than people in the United States, meaning that all the companies are competing for essentially the same customers now.

Even if the FCC shoots down a merger between Sprint and T-Mobile today, it's not hard to see something like it passing muster down the road when both companies have had a little more time to (dis)prove themselves.