2023 MLB Rules Changes

The Wikipedia page for the 2023 MLB Season has a nice summary of the MLB rules changes for 2023:

• A pitch clock will be introduced, including the following features:
  • A standardized period of 30 seconds between batters within each half-inning.
  • A timer between pitches of 15 seconds with the bases empty, and 20 seconds with at least one runner on base.
  • The pitcher must start his motion before the expiration of the pitch timer. A violation will result in an automatic ball.
  • The batter must be in the box and alert to the pitcher with no less than eight seconds remaining. A violation will result in an automatic strike.
  • With runners on base, the timer resets if the pitcher attempts a pickoff or steps off the rubber (collectively called a "disengagement").
  • Only two disengagements are allowed per plate appearance; however, this count resets if a baserunner advances. Mound visits, injury timeouts, and offensive team timeouts do not count against this.
  • On a third disengagement, an unsuccessful pickoff attempt will cause that runner to advance one base.
  • If a team has used up all of its allowed five mound visits by the ninth inning, it receives an extra visit in the ninth.
  • Umpires can provide extra time if circumstances warrant.
• Infield shifts will be severely restricted:
  • The defensive team must have no fewer than four players in infield positions, with at least two on each side of second base.
  • All infielders must have both feet on or inside the outer edge of the marked infield while the pitcher is on the rubber.
  • Infielders cannot switch sides of the infield before a pitch is released.
  • If infielders are improperly aligned at the time of the pitch, the offensive team may choose to accept the result of the play, or receive an automatic ball.
• All three bases will increase in size from 15 to 18 inches (38 to 46 cm).

2023 Major League Baseball season - Wikipedia