On Tuesday, the league sent out a memo regarding the recent trend of players jumping on another player’s back to intentionally foul them.

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“Please be advised that the referees have been instructed to evaluate such plays under all applicable playing rules, including the rules relating to Flagrant Fouls,” the league said in a statement by league vice president Kiki VanDeWeghe.  

“Players remain free to commit deliberate fouls during free-throw attempts, but such fouls will be assessed as Flagrant if they meet the applicable criteria.”

Intentionally fouling poor foul shooters as a strategy has been around for years, but it has seen an uptick lately. NBA commissioner Adam Silver said during All-Star weekend that the tactic has been used at 5 1/2 times the rate it was last season.