Two premier summer leagues -- the MLB Draft League and the Appalachian League -- begin their highly anticipated 2022 seasons tonight. These MLB-partnered leagues feature amateur standouts who could become future MLB stars, and you can watch every game for free on MLB.TV and on the league websites.

Here is what you need to know about the leagues, each of which has made some format changes following successful inaugural seasons in 2021.

MLB Draft League

A training ground for baseball's top Draft-eligible talent, the MLB Draft League saw 39 players from its inaugural 2021 rosters selected in last year's Draft. That represents 29 percent of all players taken from a summer league and more than the number of players taken from the elite college Cape Cod League (34). Plus, more than 50 other players from the MLB Draft League either signed as undrafted free agents or with an independent league.

The league was particularly helpful for junior college players, with more than 20 percent of all JUCO players taken in the 2021 Draft coming via the Draft League. A total of 10 of the 47 junior college players taken in the Draft came through the league first.

The MLB Draft League also showcases high school players, as 36.8 percent of prep players who were in the 2021 league got drafted, and 31.6 percent moved on to Division I college programs.

This year's 80-game season will be split up into two halves, with the first half running from June 2-July 16 and featuring amateur, draft-eligible players. All players who participate in the first half of the Draft League will have the opportunity to participate in a pre-Draft pro day for MLB club scouts on June 26 and 27.

Following a midseason break to coincide with the MLB All-Star break, the second half will run from July 22-Sept. 6 and will feature professional players who have exhausted their amateur eligibility or otherwise wish to begin their professional careers. It will be the first league in the country with this hybrid amateur-professional format.

On Sept. 6, the league's first- and second-half champions will meet in a winner-take-all MLB Draft League Championship Game.

Some of the new rules implemented for 2022 include "sudden death" extra innings, free player substitutions, and some seven-inning games

Appalachian League

This longtime Minor League Baseball circuit is now a wood-bat summer league for the top college freshman and sophomores. A part of the Prospect Development Pipeline, the Appalachian League offers many players their first foray into what life is like as a professional ballplayer. Players travel to and play in each of the league's 10 cities scattered throughout Appalachia. Each stadium has its own dedicated grounds crew, clubhouse manager and, of course, unique fan experience.

• Players participating in the 2022 Appalachian League

The Appalachian League will play a 58-game season from June 2-Aug. 6, culminating in a one-game championship on Aug. 8. The team with the best overall winning percentage in each of the five-team divisions (East and West) will vie for the title. The Appy League will also host an All-Star Game on July 26, as part of a two-day community event at Burlington Athletic Stadium in Burlington, N.C.

Changes to the league's format include the return of seven-inning games on Sundays and "sudden death" extra innings.