In China, the technical level of athletes is divided into international athletes, athletes, first-class athletes, second-level athletes, and third-level athletes, which are mainly evaluated according to the results of international/national competitions. In the MLB system, the promotion path of athletes is mainly achieved through the Minor League Baseball (MiLB) hierarchy system, which can be divided into the following levels:

MLB Pro Player Promotion System

Major League Baseball

The highest division, consisting of 30 teams, represents the highest level of baseball in the world.

Players must be on the team's 26-man Active Roster or 40-Man Roster roster to become a major league player.

Minor League tier

The minor leagues are MLB's talent development system, which is divided into 6 tiers (from highest to lowest):

AAA (Triple-A)

The highest level of minor leagues, where the level of players is closest to that of the major leagues, is often used as a temporary substitute for injured or reconditioned players in the major leagues.

Representative teams: Las Vegas Flyers (affiliated with Oakland Athletics), Dehan Bulls (affiliated with Tampa Bay Rays).

AA (Double-A)

A proving ground for potential rookies and near-major league players, with a focus on developing technical details and tactical execution.

Representative leagues: Eastern League, Southern League.

High-A grade

The mid-level training layer focuses on the improvement of players' special skills (such as pitcher ball control and hitter ball selection ability).

Low-A grade

In the basic professional training stage, players begin to adapt to the intensity of professional competition.

Rookie League

It is divided into the Complex League (formerly AZL/GCL) and the Independent Rookie League, which are mainly aimed at newly signed international players or high school graduates.

Dominican Summer League (DSL)

An entry-level league for international rookies aged 16-18, especially Latin American players.

Independent League

In professional leagues that are not part of the MLB system, players can compete for MLB team contracts through outstanding performance (e.g., Atlantic League, American Association).

Player development paths

Draft/International Signings

U.S. Native Players: Enter the system through the MLB Annual Draft (20 rounds), usually starting in the Rookie League or Low-A.

International players: Applicants are at least 16 years old and can be signed, most of whom started their careers in the Dominican Summer League.

Promotion logic

Players are promoted or demoted each year based on performance (e.g., batting percentage, defense rate, advanced stats), and it takes an average of 4-5 years to move from Rookie League to MLB.

Typical case: Shohei Ohtani (Japan) → directly signed with MLB through the registration system; Juan Soto (Dominican Republic) → promoted from DSL to Nationals.

40-person list rule

Players on the 40-man roster can be called up to the major leagues and may be removed from the roster if they are not promoted within three years (subject to a transfer process).

Domestic grading system: based on the results of the competition.

MLB system: With the league level as the core, emphasizing long-term competition and actual growth.

MLB's promotion system is highly market-oriented, with only about 10% of minor league players eventually making it to the major leagues, which is far more competitive than the average professional sports system.