Since 2015, the number of starters teams most often used in a full length season has been 11. That number seems to be all at once pretty large and yet still unsurprising. What’s maybe more surprising is the long righthand tail of the distribution above: a lot of teams field 12+ starting pitchers each season. On average, teams have used close to 12 (11.8) starters in the past 7 full seasons. The 2019 Blue Jays used the most distinct starters since 2015 with 21.
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This evening, the Detroit Tigers will use starting pitcher number 9, who hasn't started a major league game since 2024.
The Tigers may end up with 17-18 distinct starters this season.