When the network launched 16 months ago to about 50 million subscribers, it became the most successful channel launch in cable history. Plus, the quality of its programming has been widely praised, as it took home four statues from last month’s Sports Emmy Awards, a record haul for a first-year network.

But viewership has been slow to follow suit.

Nielsen started rating the channel at the beginning of April, giving the sports media industry its first glimpse at how many people are watching. The network’s prime-time and total day viewership place MLB Network behind other single-sport channels like Speed, Golf Channel and NFL Network. Of the Nielsen-rated sports channels, only Fox Soccer Channel averaged fewer viewers in prime time and single day in April. Some single-sport networks like NBA TV, NHL Network and Tennis Channel are not rated, primarily because they don’t have enough distribution.MLB Network executives say they are not surprised by the early ratings, which they say are in line with internal expectations and are showing an increase from last year, when the channel was not rated officially.

“We feel good about where we are,” said network President Tony Petitti. “We’re still new. We still hear from people who don’t know where to find us.”

Despite the low viewership numbers, the business metrics for the channel still appear to be strong, thanks to its dual revenue stream of advertising and license fees from cable and satellite operators.

Most importantly, the viewership numbers came in a little bit higher than some ad buyers were expecting. Larry Novenstern, a media adviser with The Leverage Agency, bought spots on the channel for Denny’s while he was an executive with Optimedia. He said the initial numbers “sound pretty good.”

“You want to under-promise and over-deliver, and it sounds like that’s exactly what Tony did,” Novenstern said.

To nobody’s surprise, MLB Network’s highest ratings come from live games and the shoulder programming that surrounds them. Its highest rating to date is a Yankees-Red Sox game from April 6, which averaged 350,000 viewers. The channel’s signature show, “MLB Tonight,” averaged 343,000 viewers that same night.

Similarly, the Angels-Yankees game on April 15 was the network’s third most viewed show of the month (322,000 viewers). “On Deck Circle,” which preceded that game, was the channel’s fifth most viewed show for the month, with 190,000 viewers.