Creator/writer Blake Masters monitors the filming of scenes from Showtime’s Brotherhood at the State House. The drama set in Providence has received glowing reviews, but it has failed to draw a large audience.

The Providence Journal / Sandor Bodo

PROVIDENCE — Pay cable channel Showtime is betting that a serial killer named Dexter will be an unlikely savior for Brotherhood, its drama set in Providence.

When the ratings-deprived Brotherhood returns to the air Sunday night at 10 o’clock for its second season, it will directly follow the second-season premiere of Dexter, one of Showtime’s most successful shows. The idea, said Showtime entertainment president Robert Greenblatt, is that the audience for Dexter will naturally flow into Brotherhood.

Last season, Brotherhood received mostly glowing reviews. It also won a prestigious Peabody award. The only thing missing was the audience.

As a rule, Showtime does not release ratings figures. Showtime’s original series, such as Dexter and Brotherhood, air several times a week, so the ratings for individual time periods don’t reflect the whole audience. Greenblatt said Showtime, as a pay cable channel, derives its income from subscribers, not from selling advertising based on the ratings, so the numbers are not as crucial as they would be for a broadcast network.

“That being said, we’re hoping more people will watch,” Greenblatt added.

Greenblatt said Showtime has 14.5 million subscribers, about half the number of rival HBO.

According to the trade journal Variety, ratings for the first-run Brotherhood episodes on Sunday nights last season averaged 241,000 viewers, although that figure does not include the additional showings of Brotherhood throughout the week. Variety reported that Dexter’s debut episode in October 2006 grabbed 603,000 viewers at 10 p.m. The Web site zap2it.com reported that Dexter’s finale in December had 1.1 million viewers.

The much hyped-finale of The Sopranos had about 12 million viewers, although the regular season episodes averaged about 8 million. A hit on one of the major broadcast networks, such as Desperate Housewives on ABC, averaged about 17.5 million viewers last season, and an immense blockbuster, such as American Idol on Fox, drew more than 30 million.

Trying to strengthen a show by giving it a stronger lead-in is common practice in network TV. Greenblatt said it’s less common on cable TV, because cable channels have fewer original series to draw on. Still, Showtime is trying it on Sunday nights with Dexter and Brotherhood and again on Monday nights with two back-to-back comedies, Weeds and Californication.

“Showtime and Bob [Greenblatt] have been massively helpful; they’ve made a huge investment in seeing us succeed,” said Blake Masters, writer and creator of Brotherhood. “They put us behind the show with the biggest buzz in their lineup.”

Masters also said that last year Showtime ran Brotherhood during the summer, traditionally not the season when people want to watch a dark, complex drama. A spot in the fall, he said, makes more sense for a show such as Brotherhood.

Dexter stars Michael C. Hall as a serial killer who spends his days working as a forensic specialist for the Miami Police Department. Although Hall’s narration, and the weird contrast between his daytime job and his nighttime compulsions, give the show some droll humor, it is still a very dark piece of work. Showtime promos are playing up the complementary nature of Dexter and Brotherhood, which is no stranger to bloodshed, either.

“We don’t expect everyone who loves Dexter will also love Brotherhood … but these are both two adult dramas with some heavy stuff going on,” Greenblatt said.

Masters said he tries not to think about ratings.

“I’m happy anyone watches at all,” he said. “I’m hoping the small, rabid core [of Brotherhood fans] can be built on. But I try to not drive myself crazy worrying about it.”

asmith@projo.com