The MLB is always three steps behind on these issues. How long have they known about pitchers using various substances to improve their grip? It's been a universally known secret that just about every pitcher uses something to this effect. Rather then set rules for what is and what isn't acceptable, they just let it slide. But now that pitchers are dominating and it's making MLB look bad, they're putting the onus on players even though MLB has been allowing them to use these substances with no repercussions for decades. It's basically the same thing that happened with steroids, just look the other way until the issue comes to a head, and then blame the players.