The Injured List
A way to replace an injured player without losing his roster spot, in three lengths.
What it actually is. A player placed on the injured list is off the active roster and cannot play, and the club may replace him. The standard list is 10 days for position players and 15 for pitchers, with a 60 day version that also opens a 40 man roster spot. There is a separate 7 day concussion list. Players returning may take a rehab assignment in the minors first.
What somebody who knows the game gets out of it. The 15 day minimum for pitchers exists because clubs were using the 10 day list as a rotation management tool, sending a healthy starter down for a turn and calling up a fresh arm. That is a good example of how every roster rule gets optimized against, and how the response is always a new rule rather than an appeal to good faith.
The numbers worth knowing. A club uses the injured list 25 to 35 times in a season. Pitchers account for the majority. A Tommy John surgery is a 12 to 18 month absence.
What people get wrong about it. The injured list is a roster tool as much as a medical one, and being on it does not mean a player is seriously hurt. The 60 day version is used mostly to free a 40 man spot for somebody already out for the season.
At Little League and travel ball. The youth equivalent is pitch count rest requirements, which are mandatory and enforceable rather than discretionary. The Pitch Planner on this site tracks them across a weekend for exactly this reason.
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