The National Association of Professional Baseball (NAPB; French: Association nationale de baseball professionnel, ANBP), formerly known as the Frontier League (FL; French: Ligue Frontière, LF), is a professional baseball league in North America. Founded in 1993, it is an official MLB Partner League. The league fielded 18 teams during the 2026 season, with 15 in the United States and three in Canada. Two additional clubs have announced plans to join for the 2027 season, bringing the league's proposed membership to 20 teams. The league office is based at ForeFront Field in Avon, Ohio.
The Frontier League was organized during the winter of 1992–1993 to bring professional baseball to communities in West Virginia, eastern Kentucky and southeastern Ohio that were unlikely to receive affiliated professional baseball clubs. It began with eight teams in 1993 and later expanded through new franchises, relocations and the 2019 merger with the Can-Am League.
Beginning in 2026, each club plays a 102-game regular-season schedule. Eight teams qualify for the postseason. The reigning league champions are the Ottawa Titans, who defeated the Evansville Otters, 3–1, in the 2026 Frontier League Championship Series to win their first title.
In April 2026, the league announced that it would rebrand as the National Association of Professional Baseball (NAPB), known in French as the Association nationale de baseball professionnel (ANBP), beginning with the 2027 season. The new branding was publicly launched on October 1, 2026, when the league introduced its new identity through its official social media accounts. The league stated that its history, statistics, records and individual team histories would continue under the new identity.
On September 30, 2026, the Kane County Cougars and Cleburne Railroaders, both previously members of the American Association of Professional Baseball, announced their intention to join the league for the 2027 season.
History
Founding and early survival The Frontier League was formed during the winter of 1992–1993 by a group seeking to establish professional baseball in smaller markets in the Ohio Valley and Appalachian region. The inaugural league had eight teams: the Chillicothe Paints, Kentucky Rifles, Lancaster Scouts, Ohio Valley Redcoats, Portsmouth Explorers, Tri-State Tomahawks, West Virginia Coal Sox and Zanesville Greys. The Greys won the first league championship.
The league's first season was unstable. The Tri-State and West Virginia clubs folded within the opening weeks, leaving six teams to complete a 50-game schedule. Bill Lee became the league's first full-time commissioner on June 1, 1994, at a time when the league's long-term survival was uncertain. Lee later said that the league's early priorities were survival, improving facilities and moving into more stable markets.
The league continued to add and relocate franchises through the 1990s. In 1999, the London Werewolves became the first Frontier League team based in Canada.
Growth and stabilization By the beginning of the 2000s, the league had begun moving into larger markets and purpose-built professional ballparks. Baseball America credited improved facilities and more stable ownership with helping the league establish a durable operating model.
On June 20, 2000, Brian Tollberg debuted for the San Diego Padres, becoming the first former Frontier League player to reach Major League Baseball. One week later, Morgan Burkhart debuted with the Boston Red Sox. The number of former Frontier League players reaching affiliated baseball continued to grow during the decade.
Attendance also increased substantially. The league drew approximately 719,000 fans in 2001 and more than 950,000 in 2002. Nearly 1.3 million fans attended games in 2004, when the Gateway Grizzlies became the first league club to draw more than 200,000 fans in a season and average more than 4,000 per game. In 2007, the league set a then-record with approximately 1.5 million fans across 12 clubs. The newly established Southern Illinois Miners drew a league-record 259,392 fans that season and averaged more than 5,000 per game.
Lee served as commissioner for 27 years before stepping down in 2021 and becoming commissioner emeritus.
Can-Am League merger and MLB partnership On October 16, 2019, the Frontier League announced a merger with the Can-Am League. The New Jersey Jackals, Rockland Boulders, Québec Capitales, Sussex County Miners and Trois-Rivières Aigles joined the Frontier League, while the Ottawa Champions were not included. The combined league was scheduled to begin play in 2020, but the season was canceled because of the COVID-19 pandemic.
On September 24, 2020, Major League Baseball designated the Frontier League as an official MLB Partner League. The partnership formalized cooperation between MLB and the league on player development and other baseball initiatives.
Pandemic and Canadian border issues Ottawa was awarded a new Frontier League franchise in September 2020, while the Tri-City ValleyCats joined in January 2021 after the reorganization of Minor League Baseball ended the New York–Penn League.
Continued restrictions at the Canada–United States border prevented the Ottawa Titans, Québec Capitales and Trois-Rivières Aigles from operating normally in 2021. Players from the three organizations were combined into Équipe Québec, which began the season as a traveling team before later playing home games in Quebec City and Trois-Rivières. Ottawa did not play a regular Frontier League season until 2022.
Expansion and national growth The Southern Illinois Miners ceased operations after the 2021 season when owners Jayne and John Simmons retired from professional baseball. The league subsequently used the Empire State Greys as a traveling team during the 2022 and 2023 seasons.
In April 2022, the league introduced a new visual identity designed by Brian Gundell Design. The logo featured a compass symbolizing the league's geographic expansion and forward direction, with red and blue representing its Canadian and American markets, respectively.
A new franchise at Campanelli Stadium in Brockton, Massachusetts, began play as the New England Knockouts in 2024. After one season, the club was renamed the Brockton Rox.
In September 2024, the league announced two southeastern expansion franchises for the 2025 season. The Mississippi Mud Monsters in Pearl, Mississippi, were announced on September 9 as the league's 17th team following the departure of the Mississippi Braves from Trustmark Park. The Down East Bird Dawgs in Kinston, North Carolina, were announced eight days later as the 18th club and began play at Grainger Stadium, the former home of the Down East Wood Ducks. Both began play in 2025.
The league reported four consecutive regular-season attendance records from 2022 through 2025. Nearly 1.9 million fans attended games in 2025, while 26 players had contracts acquired by Major League Baseball organizations; 22 of those players had no previous professional experience outside the Frontier League. The league again fielded 18 teams in 2026 and expanded the regular season from 96 to 102 games. On May 8, 2026, the Ottawa Titans sold 10,278 tickets for their home opener, establishing a new Frontier League single-game attendance record.
On September 30, 2026, the league announced that the Kane County Cougars and Cleburne Railroaders intended to join for the 2027 season, moving from the American Association of Professional Baseball.
Rebrand to National Association of Professional Baseball On April 22, 2026, the Frontier League announced that it would compete as the National Association of Professional Baseball beginning with the 2027 season. The league said the change followed a strategic planning process that began in fall 2024 and reflected the circuit's expansion beyond the regional geography implied by the Frontier League name.
The NAPB brand strategy uses the phrase North America's Home Teams. Its visual identity includes an "NA" monogram with a pennant and French-language versions for the league's Canadian markets. The full identity was presented publicly during the league's 2026 All-Star festivities in Florence, Kentucky. The league stated that its 34-year history, records and individual team histories would continue under the new identity.
League leadership Bill Lee served as commissioner from June 1994 until 2021 and remained associated with the league as commissioner emeritus after his retirement. He was inducted into the Frontier League Hall of Fame in 2024.
Steve Tahsler was named commissioner in 2023 after 14 years as deputy commissioner. Tahsler had previously worked in several Frontier League front offices, including as general manager of the Windy City ThunderBolts, Slippery Rock Sliders, Evansville Otters and Dubois County Dragons.
Season structure The Frontier League season includes spring training and exhibition games in late April and early May, a regular season from May through early September, and a postseason that runs into September. Beginning in 2026, all 18 teams play 102 regular-season games.
The league uses two conferences, Atlantic and Midwest, each divided into two divisions. Eight teams qualify for the postseason: the four division winners and two wild-card clubs from each conference. The playoffs are played in three rounds and culminate in the Frontier League Championship Series.
Since 2022, the league has used a sudden-death format to decide games that remain tied after 10 innings. In sudden death, the home manager chooses whether the home team will bat or field for a single half-inning. If the defensive team prevents the offensive team from scoring, the defensive team wins; if the offensive team scores, it wins. In August 2024, the Lake Erie Crushers became the first professional baseball team to win a game without scoring a run when they defeated Schaumburg through the rule after 10 scoreless innings.
Players and professional development Frontier League clubs recruit and sign their own players. The league's roster classifications are designed to reserve a substantial portion of each roster for younger professionals while limiting the number of older or more experienced players. As of 2026, regular-season and playoff rosters consist of 22 to 25 active players. Clubs must carry at least 10 players classified as Professional-1 or Professional-2 and at least six Experienced-1 players, while no more than eight players may be Experienced-2 or Veteran and no more than two may be classified as Veterans.
The league also operates an annual tryout camp and player draft. The 2026 event was the 33rd annual Frontier League Tryout Camp and Draft.
MLB describes the Frontier League as a player-development pathway and states that the league has placed more than 1,000 players into Major League organizations, with more than half beginning their professional careers in the Frontier League. Brian Tollberg was the first league alumnus to reach the major leagues in 2000, followed a week later by Morgan Burkhart. In 2025, the league reported 26 player contracts acquired by MLB organizations, including 22 players whose only previous professional experience had been in the Frontier League.
Teams
The league uses a two-conference, four-division alignment. The Atlantic Conference consists of the East and North divisions, while the Midwest Conference consists of the Central and West divisions. All 18 permanent clubs competed in the 2026 season.
List of teams