For now, N.P.F. is taking a measured approach to expansion, with hopes of adding a team or two each season over the next few years. The league is national in scope, but there is no geographic master plan.  Team owners’ experience and financial qualifications matter to Kempf more than their locations. The league has two Texas-based teams, the Scrap Yard Dawgs and the Charge, but Kempf is open to adding more — assuming they have sound business plans. But Southern California, arguably the biggest softball hotbed in the country and home to many top college players, has yet to have a team in the league because no qualified owners there have come forward.  But the growing popularity of college softball is a positive sign for the league’s future. The finals of the Women’s College World Series this season had the second-highest television ratings in the championship’s history, behind last year. N.P.F. teams used to rely on Olympic stars to bring in crowds, but today’s top college players attract similar attention.  The Pride, which featured seven former Olympians on its roster just six years ago, is now built around players like Keilani Ricketts and Sierra Romero who became household names in college, thanks to ESPN’s increasingly prominent coverage of the N.C.A.A. tournament.  “We have more girls playing softball than ever before and starting at younger and younger ages,” said Don DeDonatis, the Pride’s owner and manager. “Our current team could be better than that original team, to be honest.”  Get daily updates during the Olympics as well as a weekly roundup of sports news.  N.P.F.’s ties to the college game also help with community outreach. Aside from the occasional story on high-profile players like Abbott, N.P.F. teams do not receive much news coverage. Even some college players are unaware that the league exists. The pro teams have been working to change that by playing games on college campuses. Starting Aug. 19, the N.P.F. championship will also be held at a major college stadium, at the University of Alabama, for the first time.  More professional softball teams would enable more college players to stay in the sport after graduation. Some Americans, including Ricketts and Abbott, also play in Japan’s professional softball league, but each of its 12 teams is allowed to have only two foreign players, putting those spots out of reach for most college players. (In recent years, several foreign players have played in N.P.F., which has no roster restrictions.)  With roughly 300 Division I college softball teams producing players, N.P.F. could quadruple in size and still not come close to exhausting the supply of players graduating each spring. Despite Abbott’s record contract, most player salaries range from $3,000 to $10,000 per season, and as in other women’s professional sports, players need day jobs to make ends meet.  Not long ago, N.P.F.’s future seemed uncertain. Its three stable teams may have been the best in the world, but without growth, the league had little chance of survival. Today, the league is growing and re-energized. A 25-game broadcast deal with CBS Sports Network takes effect next year. The International Olympic Committee will vote this week on whether to bring back softball for the 2020 Olympics, which will be held in Tokyo, where the sport is popular.  “What’s happening now is that there’s people saying, ‘Hey, this is a great game,’” DeDonatis said. “I’m always pushing it. All I talk about is women’s softball.”  An earlier version of a caption with this article misspelled the surname of a softball pitcher who signed a $1 million contract. She is Monica Abbott, not Abbot.  Erica Westly is the author of “Fastpitch: The Untold History of Softball and the Women Who Made the Game.”  A version of this article appears in print on July 31, 2016, on page SP5 of the New York edition with the headline: With a Million-Dollar Arm, a League Makes Its Pitch. Order Reprints| Today's Paper|Subscribe
Monica Abbott signed a $1 million contract with the newest National Pro Fastpitch franchise in May, a sign that the league is ready to grow. But to do so, it may need corporate sponsors.