Less than three months after Comcast Corp.’s NBCUniversal committed to spend about $950 million to air English Premier League soccer games in the U.S., the deal is starting to look like a rare commodity in the hot market for sports rights: a bargain.

In August, when the media company announced the new deal, which extends an earlier partnership and spans the 2016-17 season through 2021-22, NBC Sports Chairman Mark Lazarus predicted the company wouldn’t make money on the transaction, positioning it more as a loss-leader that...