ST. PETERSBURG, Fla. – Downtown may be booming, but in an already-saturated professional sports market with few Fortune 500 companies, St. Petersburg may be hard-pressed to support another major league-level team.

That means the next mayor may help determine if the city will be the long-term home to a major league baseball team or a major league soccer team.

Tens of thousands of St. Petersburg residents have now received ballots in the mail for the city’s Aug. 29 mayoral primary, where incumbent Mayor Rick Kriseman is trying to fend off a challenge from former mayor Rick Baker. There are four other fringe candidates in the non-partisan race, so if neither Baker nor Kriseman accumulates 50 percent of the vote, the two will head to a November run-off.

During recent sit-down interviews, both candidates told 10Investigates they thought the city could support two pro teams; the Tampa Bay Rowdies are campaigning to expand Al Lang Stadium and climb to the Major League Soccer (MLS) ranks, while the Tampa Bay Rays are looking for a new long-term baseball home in either St. Petersburg or Tampa.

However, the Rays have complained about a lack of corporate support for years and disposable income levels around Tampa Bay remain among the lowest in the nation’s large metros. Adding a second major draw in St. Pete – in addition to the Buccaneers and Lightning in Tampa, plus numerous minor league teams around the region – would only stress the market further, according to Forbes’ sports business writer Maury Brown.

“People have a limited discretionary income,” Brown said. “Some people will be able to go to two or three (teams over the course of a year) but some will have to pick and choose.

“You’re always going to be looking (at) whether you are cannibalize your corporate base or your attendance base.”

Is St. Pete big enough for MLB and MLS?

Some of the main findings of the ABC Coalition, the group created by then-mayor Baker in 2008 to explore the long-term feasibility of keeping the Rays, was that the team suffered from a lack of both population and corporations located within a 30-minute drive of its stadium.

In 2010, team owner Stu Sternberg told the region the team needed a new home “in a place that makes us attractive to the region’s businesses and community. For this franchise to survive, it needs to have the support of the businesses of Tampa Bay.”

Since that press conference, the team’s attendance has continued to slide almost every year, now hovering at just more than 15,600 fans per game – by far, the worst mark in the majors.

FLASHBACK 2010 blogpost: Are Rays creating a self-fulfilling prophecy?

So even though both Kriseman and Baker said they were confident the city was big enough for both the Rays and Rowdies to grow and succeed long-term, the numbers suggest otherwise.

With a population of 261,000, St. Petersburg is major league baseball’s smallest home city. The Tampa Bay region is home to only four Fortune 500 companies. Recent market studies have suggested Tampa Bay is running a “substantial deficit” of total personal income, and there is “insufficient” capacity for any new teams.

Rowdies owner Bill Edwards and his top deputy, former mayor Baker, have steadfastly claimed the Rowdies could draw 18,000-20,000 in St. Pete as an MLS team.

“The Rays are in a bit of a bind right now,” Brown said. “If they have a new facility, I think there’s little doubting that there’d be would be increased attendance and that there’d be other corporate members that would want to jump onboard. But when you add another (major-league) franchise into the dilutes the market.”

The Rowdies joined the city of St. Pete to launch an “MLS2StPete” campaign, targeting the league’s expected winter expansion. Many cities vie for two spots, but Edwards is one of the only bidders who promised to pay for $80 million in stadium upgrades himself, as well as the $150 million MLS expansion fee. The team’s long-term lease with the city would likely be negotiated by whichever administration wins the mayoral election: incumbent Mayor Kriseman, or Edwards ally Baker.

Watch on Mobile: Forbes' Maury Brown speaks on the Rays' corporate support

Which candidate is favored by which team?

While neither candidate indicated he preferred one team over another, the willingness to offer the Rays public subsidies could determine if the team stays in St. Pete for another generation.

Kriseman has already made an initial public offer to the Rays, which included city redevelopment rights to the public land at Tropicana Field, city general revenue tax dollar funds, as well as an assumed contribution from county bed tax revenues. He said it’s a far-sweeter package than his counterparts in Tampa could offer.

But at a time when the city wants to raise fees on residents to fund sewer and infrastructure fixes, Baker suggested general revenue tax dollars should not yet be offered to the Rays. He said he preferred to save the money, if possible, and only give the team county dollars and the rights to redevelopment around a new stadium. Baker, however, would not discuss additional specifics, saying he didn’t want to “negotiate publicly in the media.”

Both Kriseman and Baker have pledged not to raise taxes in order to build a stadium.

But Kriseman’s willingness to spend general revenue money on a Rays stadium could force the city to raise other fees. It was reported this week the city now wants to raise utility fees to pay for the sewer project, while still preserving general revenue dollars in case the Rays need help building a new home downtown.

When 10Investigates reported in April that proposed stadium dollars could help the city pay for its sewer fixes, Kriseman’s communications director, Ben Kirby, pushed back, claiming the infrastructure work was “already paid for.” But this week’s proposed rate hike contradicts the claim.

Kriseman said his willingness to work with the Rays and allow them to explore stadium sites in both Pinellas and Hillsborough counties – a deal Baker opposed – will keep the team in the area for future generations. He said it's also beneficial to St. Pete, even if the team leaves.

“(The deal) allowed us to start planning for what’s going to be on that Tropicana Field site with or without a team,” Kriseman said. “Very few communities around the country have 86 contiguous acres that are owned by the public that can be redeveloped.”

Kriseman has also met with MLB Commissioner Rob Manfred. He also said the Rowdies could one day wind up at the Trop site if the Rays leave.

WATCH: Kriseman, Baker discuss possible stadium at redeveloped Trop site

Rays executives and owners have rewarded Kriseman with at least $31,500 in contributions to his political action committee. That includes $9,000 from principal owner Stu Sternberg.

Meanwhile, Baker has led the MLS-to-St. Pete charge and has received $50,000 in PAC contributions from his boss and team owner, Bill Edwards.

Baker says, however, he would negotiate just as hard for the city with Edwards as he would with the Rays.

“When I was mayor before, nobody ever doubted that I was going to fight for the city all the way,” Baker said.

The Rays declined to comment on this story, but are expected to be active participants in the stadium conversation this upcoming offseason, when Hillsborough County could publicizes its top site(s) for a possible new stadium.

In a recent Tampa Bay Times article, Sternberg was quoted, "We've worked with both the mayoral candidates in the past and we've had good experiences with both of them at times."

A spokesperson for Bill Edwards says the Rowdies’ owner has officially endorsed Baker’s candidacy.

Photo illustration of prominent PAC donors for Rick Baker (left) and Rick Kriseman (right).
Photo illustration of prominent PAC donors for Rick Baker (left) and Rick Kriseman (right).

Other sports-related issues

In recent years, professional teams have started making more money on ancillary development around their facilities, rather than just counting on revenues that come from ticket and concession sales inside a stadium. It has allowed St. Pete to make the case that the Rays should stay where they are and build a new home at the existing Tropicana Field site.

Kriseman offered the Rays significant redevelopment rights to the site if they stay. Baker indicated those future revenues would be his preferred method of financing a ballpark, although he deflected direct questions about how he would negotiate with the team.

Brown says more owners are looking for opportunities to profit off mixed-use development around a stadium. And that could help St. Pete put together a tempting package for the Rays.

“There’s nothing to say a brand-new shiny ballpark will be enough (for the Rays),” Brown said. “If they have another revenue source to offset some of (the construction costs), and it's in a downtown location, I think that really helps.”

Watch on mobile: Forbes' Maury Brown comments on Rays development in St. Petersburg

Another area Kriseman and Baker differ with regards to sports teams is in their support for mass transit, seen as a possible game-changer for the Rays and other teams.

Kriseman has been a tireless advocate for rail, improved bus service, and the Cross-Bay Ferry. Baker has taken a more cautious approach toward transit, telling 10Investigates he preferred the county take the lead on the issue.

10Investigates also reached out to the four other candidates in the St. Pete mayor’s race, but none responded to emails, and none are expected to draw a significant number of votes.

UPDATE 8/10: Candidate Jesse Nevel issued a statement that said his plan for the stadium "is a wrecking ball" and his plan for the 85 city-owned acres at Tropicana Field would be to have it "returned to the black community as a means to repair the damage, unite this city, and get on the right side of the question."

The city’s primary election is Aug. 29; if no mayoral candidate garners 50 percent of the votes, a run-off will be held on Nov. 7.

Find 10Investigates reporter Noah Pransky on Facebook or follow his updates on Twitter. Read his Sports Business Blog at Shadow of the Stadium.