MLB has released new guidelines for the enforcement of the rules against applying foreign substances on baseballs. These new guidelines will go into effect beginning on Monday, June 21, 2021.
As you can read in the link above, MLB says that their investigation has found a “prevalence of foreign substance use by pitchers” both in the majors and in the minors, and that the use of the foreign substances have a material impact on performance. Because of that, there will be a new enforcement system in place beginning next week.
The link above has highlights of the new guidelines, but umpires will check starting pitchers more than once per game, and relief pitchers will be checked either when they are pulled from a game or when they have finished an inning, whichever comes first. Umpires can also do spot checks if they notice a baseball that has “an unusually sticky feel to it,” or if the umpire sees a pitcher touching any part of his uniform or body in a way that suggests he may be applying something to the ball.
Violators will be suspended for ten games, and teams will not be allowed to replace a suspended player on the roster during the duration of the suspension.