Major League Baseball issued a memo to each of the 30 teams on Friday that detailed what will be a much more rigorous crackdown on foreign substances -- the so-called "sticky stuff" -- being used by pitchers, according to Tom Verducci of SI.com

In the memo, written by senior vice president of baseball operations Mike Hill, is the following, per Verducci: 

"If an umpire's inspection reveals that the pitcher's hand is unquestionably sticky or shows unmistakable signs of the presence of a foreign substance, the umpire will conclude that the pitcher was applying a foreign substance to the baseball for the purpose of gaining an unfair competitive advantage."  

"If an umpire observes a pitcher attempt to wipe off his hands prior to an inspection he may be subject to immediate ejection."

Further, starting pitchers can "expect more than one mandatory check per game" while relievers will be subject to at least one and position players could also be checked. 

The increased attention on the checks will start immediately in spring training. Players showing evidence of having used a foreign substance are in violation of MLB rules and will face immediate ejection and suspension. 

Fans everywhere recall the spectacle that started last June when umpires started checking pitchers' hats, belts and gloves as they exited the field, either at the conclusion of an inning or after being removed from the game. This was in reaction to years of neglect when it came to monitoring the use of illegal foreign substances by pitchers, which can alter the way the baseball behaves on pitches and gives the pitcher an advantage over the hitter (for more on why this happened, here's an explainer). 

The initial crackdown seemed to work, but then late in the season, studies showed a spike of spin rate, suggesting the pitchers were finding new ways to get around the checks and still doctor the baseballs. 

As such, the league is now reacting with a newly-strenuous system of checking players. 

It appears this is a bit of a cat-and-mouse game. Expect the players to keep searching for ways around the inspections while the league tries to keep up and punish anyone who is caught doing so.