Starters will be subject to more than one mandatory check each game and relief pitchers must be checked once they conclude an inning in which they entered a game or when they are removed from a game, whichever comes first, MLB said.
Club employees who assist players in using or masking foreign substances or who refuse to cooperate or who fail to report violations will be subject to fines and suspensions.
Rosin bags will continue to be allowed but rosin cannot be combined with sunscreen or other substances, and pitchers are being told not to use sunscreen after sunset in outdoor stadiums and not to use it at all in indoor ballparks.
That research concluded that foreign substances significantly increase the spin rate and movement of the baseball, providing pitchers who use these substances with an unfair competitive advantage over hitters and pitchers who do not use foreign substances, and results in less action on the field.
Executive vice president for operations Morgan Sword, MLB senior vice president for on-field operations Mike Hill and consultant Theo Epstein outlined the increased enforcement during a 15-minute electronic meeting Tuesday with the 30 managers.
“Unfortunately, the enhanced monitoring we implemented at the start of the season has had no impact on the behavior of many pitchers.
“This is not about any individual player or club, or placing blame,” Manfred said.
Some teams already have asked pitchers who relied heavily on foreign substances to throw bullpen sessions without any grip enhancers to prepare for the future, two players and an official told Passan.
That sort of preparation portends a change that already has taken root.