Michael Hill, the former Marlins general manger and senior vice president for operations on-field, announced the penalty just two days after Santiago was removed from a game at Chicago White Sox. Santiago was also fined an undisclosed amount.
The suspension will be delayed until John McHale Jr., the MLB special advisor, appeals the decision.
Scott Servais, the Seattle manager, insisted that Santiago's glove was free of foreign substances before Tuesday's match against Toronto. He said it was rosin.
It was rosin, and rosin is behind pitcher's mound so it's not alien. It isn't a foreign substance," Servais stated. "So, I am surprised to some extent. I do understand what Major League Baseball wants to do. They want to level the playing field. And why they did this in the middle.
Santiago, a left-hander aged 33, is playing in his 10th major league season. This will be his first season with the Mariners.
All pitchers will be checked by umpires for illicit grip aids. Santiago was also examined after he left the game in the fifth inning.
Santiago began the season at Triple-A. He made his big league debut with the Mariners in June 1. He is currently 1-1 and has a 2.65 ERA through nine games.
Seattle will not allow Santiago to be filled on its 26-man roster roster. Instead, Seattle will play a man short until a penalty is served.
Servais stated that Santiago was a pitcher he respected and encouraged. He also said that Santiago had been a good friend to him.
"When we do the right thing, it's following the rule and then lo! something like this happens," Servais stated. "It is currently going through the appeals process. We'll wait to see what happens from there."
Concerned about the offense at baseball that has dropped to its lowest point in 50 years, officials first mentioned the crackdown June 3. Commissioner Rob Manfred then announced the date for the crackdown June 15.
He stated that foreign substance use has evolved from a desire to grip the ball better to something else. This creates an unfair competitive advantage and a lack action.
Since June 3, the average pitch spin rate has fallen to 3.