MLB memo says further crackdowns on 'sticky stuff' coming this season

This season will see umpires not only examining pitchers' hats, gloves and belts, but more scrutiny will be involved when checking pitchers' hands, as well. 

"Beginning in spring training games this weekend and throughout the season, umpires will inspect a pitcher's hand, top, and bottom, when conducting random between-innings inspections," Verducci wrote. "Umpires can still examine a pitcher's hat, belt, and glove, as was done last season starting in June." 

According to the memo, catchers and position players will be held to the same standards. Also, relief pitchers will be checked at least once a game. 

Verducci went on to say the league is taking action due to data that shows pitchers found ways to get around the checks after they were implemented last season. 

Last season, comparing spin rates of four-seam fastballs and sliders showed a steep decline in RPMs once the league announced crackdowns on sticky substances. However, by the end of the season, those numbers started to climb back to levels seen before rules were introduced in June. 

Like RPMs, velocity and spin rate took a huge dive when crackdowns began, only to rise toward the latter part of the season. 

"MLB is reacting to data that suggests pitchers learned to circumvent the checks," Verducci wrote. "If they did not store a supply of sticky substance on their hat, belt, or glove, they could avoid detection. The new protocols assume no matter the method, a pitcher who uses a sticky substance eventually will have it on his hand or fingers, thus the additional level of inspection by MLB."