What you need to know about MLB's new rules

Bigger rosters, pitcher usage rules, it's about to be a different ballgame. Orlin Wagner/AP Photo

MLB and the MLB Players Association have agreed to a deal that will enact several new rules starting in the 2019 and 2020 seasons. Here are some of the most notable rule changes and what they might mean for the game, both on and off the field.

Rule effective for 2019: One MLB trade deadline

Say goodbye to extensive explanations of the procedure for waiver trades in August, because those deals are no longer on the table. The MLB trade deadline will remain July 31, and waiver trades after that date will no longer be allowed.

Looking back to past high-impact waiver deals, some notable previous August trades include:

2017: Detroit Tigers veteran ace Justin Verlander going to the Houston Astros; Verlander went 9-1 with 1.66 ERA in 11 games (10 starts) with Houston.

2012: The Los Angeles Dodgers acquired Adrian Gonzalez, Josh Beckett and Carl Crawford in a trade with the Boston Red Sox. Though the players' performances had minimal impact on the teams, the Red Sox shedding those players' contracts freed up salary space for 2013, when they would go on to win the World Series.

2008: The Toronto Blue Jays acquired Jose Bautista from the Pirates; Bautista is second all time among Blue Jays position players with 37.0 career WAR

1992: Jose Canseco was sent to the Texas Rangers in 1992 by an Oakland Athletics team en route to winning the AL West, in exchange for RF Ruben Sierra, closer Jeff Russell and starting pitcher Bobby Witt.

1990: The Boston Red Sox sent Jeff Bagwell to the Astros for reliever Larry Andersen; Bagwell would spend his entire 15-year MLB career with Houston and became a Hall of Famer

Rules effective in 2020

Roster expansion (and contraction): MLB roster size will expand from a minimum of 25 to 26 players for the entirety of the MLB regular season, but rosters in September will be limited to 28 maximum players instead of up to 40. With the changes in roster size, this could have an impact on who gets called up in September.

Prominent September call-ups of the recent past include Francisco Rodriguez by the Angels in 2002; he notched five postseason wins that year with 28 strikeouts in 18 innings en route to helping the Angels win the World Series. David Price was also originally a September call-up, with the Tampa Bay Rays in 2008; he recorded the save in Game 7 of the AL Championship Series that won the pennant for the Rays.

Pitchers must face a minimum of three batters: Starting in 2020, starting pitchers and relief pitchers must pitch to either a minimum of three batters or to the end of a half-inning (with exceptions for injury and illness).

To get a sense of the impact this rule might have, there were 2,303 outings of pitchers facing fewer than three batters in the 2018 regular season -- nearly one per game. The 11 pitchers with the most "short" outings in 2018 were all lefties.

The amount of outings facing two batters or fewer has increased steadily leaguewide throughout the live ball era, but has nearly tripled over the past 30 years.

No position players pitching outside of extra innings or score margins of seven-plus runs: Last year, MLB set a record for most position players pitching in the expansion era, as 49 position players took the mound. However, that total includes dual-threat Shohei Ohtani, who made 10 starts for the Angels as well as playing in 104 games as a hitter.

However, the rule might not diminish the total number of position players pitching. Of the 65 non-Ohtani outings on the mound made by position players in 2018, only five would have been illegal under the impending rule. All five came with their respective teams trailing by six runs, one shy of what will be the new "legal" limit.