New sports franchises are popping up all over the Salt Lake Valley. How many is too many?

Over five decades in football, Dennis Erickson has had more job offers than he can count. They’ve come from colleges, NFL franchises — and a bunch of people promising opportunities in upstart leagues. But it wasn’t until now that Erickson finally said yes to one of the newcomers, agreeing to become the head coach of a Salt Lake City team in the new Alliance of American Football League.

“I’ve had opportunities to coach in leagues like this, but this is, by far, the best and most organized,” the 71-year-old Erickson said earlier this month at Rice-Eccles Stadium, where his new team is set to begin play in February.

Many of those other leagues have come and gone. This one, Erickson said, will be different. David Webb, the director of operations for the minor-league Utah Browns, feels the same way about his team. So does Kimball Kjar, the general manager of Major League Rugby’s Utah Warriors.

The state’s newest sporting startups are hopeful they can carve out a place of their own in a market that has been dominated by the Utah Jazz, college football and, more recently, Real Salt Lake. But are there enough eyeballs and dollars among the million people in the Salt Lake Valley to sustain them all?

“That, of course, is the billion-dollar question,” said Stephen Maisch, a professor of sports economics at the University of Utah. “What sort of demand is there for any one particular thing?”

The executives at Rio Tinto Stadium have seen what it takes to survive in the market. Real Salt Lake arrived in Utah in 2004 and has built a loyal following, frequently selling out the 19,000-capacity stadium.

“There was risk associated with bring a franchise here,” said Andy Carroll, the team’s chief business officer. “You have to give them credit for having the vision to envision what exists right now.”

Over the past few years, RSL has expanded its brand to include a minor-league franchise (the Real Monarchs) and a professional women’s soccer team (the Utah Royals).

“It has potential to cannibalize the fanbase some,” Carroll said. “We’re in the entertainment business. We look at even big blockbuster movies [as competition] because people have only so much discretionary income. It’s highly competitive in that regard. …

“But we absolutely love Utah as a sports community.”

When the Utah Warriors joined Major League Rugby and played the first game in franchise history this spring, 9,000 people showed up. Since moving their games to a smaller venue in Herriman, officials hoped to be selling out that 5,000-seat stadium, but attendance has been closer to 3,500. Still, Kjar is optimistic about his team’s future thanks to the growth of youth rugby, his league’s TV deal with CBS and a lucrative jersey sponsorship.

“With ticket sales and sponsorships, I would say we’re ahead of where I thought we’d be at this point,” Kjar said.

As he considers the market and the products being offered, Maisch believes there are factors that bode well for the upstarts. Rugby has a niche but growing audience. The new Alliance football league won’t compete with the NFL’s schedule. And both of the new ventures have followed Major League Soccer’s single-entity model, allowing the league to support fledgling teams and provide enough of a runway to achieve sustainability.

“These single-entity leagues could be able to keep the whole league afloat long enough to generate a fanbase where there might not have been one,” Maisch said. “You’ve got to stick around long enough to create fans.”

Webb knows that well. At different times he’s had a hand in two Utah arena football teams, the Utah Blaze and the Screaming Eagles. Neither franchise exists today.

“We’ve had all these teams that for whatever reason have let fans down,” said Webb, whose team will begin its season next month and play games at Murray High School. “That’s the approach we’re coming from. We can’t let fans down. People are obviously skeptical that it’s just another team that’s going to be one-and-done.”