Umpires Phil Cuzzi (10) and Mark Ripperger (90) check Seattle Mariners relief pitcher Hector Santiago (57) glove for illegal substance before ejecting him. Kamil Krzaczynski-USA TODAY Sports

Hector Santiago insists he did not have an illegal substance on his glove when he was ejected from Sunday’s game, but Major League Baseball believes the Seattle Mariners pitcher was cheating.

MLB announced on Tuesday that Santiago has been suspended 10 games for having an illegal foreign substance on his glove. The left-hander is planning to appeal.

Santiago came on to pitch for the Mariners in the third inning of their game against the Chicago White Sox. He got through two innings without allowing a run, and his glove was inspected after manager Scott Servais removed him with one out in the bottom of the fifth. Home plate umpire Phil Cuzzi determined that Santiago had some sort of sticky substance on his glove, so he was ejected. You can see the video here.

Santiago said after the game that he used nothing but rosin, which is legal. He said it must have become sticky because he was sweating. His glove was placed into a plastic bag for further inspection after he was ejected.

MLB began conducting checks on pitchers last week as part of a crackdown on foreign substance use. Multiple pitchers have been furious after being checked, with some even partially undressing on the field to prove they had nothing to hide.

The new policy calls for any player who is found guilty of using an illegal foreign substance to be suspended 10 games for a first offense. Santiago is the first player to be ejected and suspended under the new rules.

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