MLB implemented significant change earlier this season by beginning to enforce its rules against the use of foreign substances on baseballs.
The league reached such a decision in the wake of offense dropping to historic lows across the sport. MLB attributed the drop-off in production to pitchers applying sticky substances to baseballs, which helped them increase their spin rates and improve command.
Ever since reports began to surface that MLB was planning a crackdown on the use of foreign substances, spin rates dropped around the league and more runs started being scored. Some pitchers have since seen an increase in spin rate, but levels remain lower than before the change.