Major League Baseball began cracking down this week on enforcement of their foreign-substances ban. That means umpires are checking pitchers regularly throughout the game for tar or tack or sunscreen hidden anywhere such as their glove or cap or belt or uniform. Every pitcher who appears in the game must be inspected at least once, and nobody can use anything except the rosin bag available on the mound.
Pitchers are not happy about this, partly because of the specifics of the rule but more because of the way it was imposed midway through a season instead of being safely rolled out when they had time to adjust to it.