League rules
KBO Roster Rules Explained - First-Team Entry, the 10-Day Rule and the Injured List
Follow Korean baseball news for a few days and you will see the same kind of headline over and over: a player has been “removed from the first-team entry” or “registered” again. Sometimes the reason is an injury, sometimes it is form or rest. Whether a player is simply removed or placed on the injured list makes a real difference, both to the player and to the club. This guide walks through how the KBO first-team roster works, what the injured list changes, and what happens when a foreign player gets hurt.
How big is a KBO first-team roster?
The KBO separates registered players (the first-team entry) from the number of players who can actually take part in a given game.
| Period | Registered | Eligible to play | Notes |
|---|---|---|---|
| Up to 2025 | 28 | 26 | Long-standing limit |
| 2026 standard | 29 | 27 | One extra place each, tied to the new Asia quota |
| 2026 second half | 30 | 28 | Temporary step for Asian Games call-ups |
| 2026 expanded roster | Up to 34 | Up to 32 | From 25 August, four extra places |
Expanded rosters used to start on 1 September with five extra places. At a June 2026 executive committee meeting, the KBO moved the start to 25 August and trimmed the increase to four places, because the standard roster had already grown by one, keeping the overall maximum the same. From 2026 teams can also add two extra players on doubleheader days.
Ordinary removal and the 10-day rule
A player removed from the first-team entry cannot be registered again until 10 days have passed. That rule forces clubs into a judgement call with minor knocks: send the player down and lose him for at least ten days, or keep him on the bench and play short-handed for a few games while he recovers.
Days spent off the roster after an ordinary removal also do not count as registration days. Registration days matter a great deal in Korea, because they decide when a player qualifies for free agency or for a move overseas. Before 2020, an injured player who was removed lost both games and service time, which is exactly the problem the injured list was designed to fix.
The KBO injured list
The KBO introduced its injured list in the 2020 season, with a similar purpose to MLB’s IL: letting a club take an injured player off the active roster without penalising the player. Reports from its first season describe the main features:
- Eligibility: a player on the active roster who is injured in a KBO regular-season game or in training.
- Application: the club files a request with the KBO, attaching a diagnosis from the club’s designated hospital, within three days of the day after the player’s last appearance.
- Length: placements are made in 10-, 15- or 30-day units. In the first season, clubs could use up to 30 days per player per season.
- Service time: while on the injured list, the player keeps earning registration days even though he is off the first-team entry. That is the biggest difference from an ordinary removal.
In the first season, players could come back before their placement ran out. At the end of 2020 the KBO board tightened this, so a player placed on the list must wait at least 10 days before being registered again. Details such as seasonal limits may continue to change through later rule revisions.
In short, the injured list keeps the player out for a similar minimum period to an ordinary removal, but protects his service time. Regular starters who get hurt are therefore almost always placed on the injured list. It cannot be used for players who are simply out of form or being rested; those moves are ordinary removals. A 2025 case also highlighted that a player injured while not on active status, such as one on military reserve, cannot be placed on the list.
Changes for the 2026 season
Ahead of 2026, the KBO revised the injured list again. Its official “what’s new for 2026” announcement lists three changes:
- Pre-season injuries: an injury suffered after the start of exhibition games can now qualify, as long as the club applies within three days of the opening-day roster being announced.
- Extensions: a player whose placement is extended for the same injury can be re-registered before the 10-day mark.
- Missed applications: if a player was clearly injured and off the roster for 30 days or more but the club failed to apply, it can submit supporting documents up to the end of the postseason. If the KBO approves, the registration days are credited retroactively, up to three times per club per year.
Foreign player rules
Roster limits: with the Asia quota starting in 2026, clubs can hold up to four foreign players, the usual three plus one Asia quota player, and all four may play in the same game. The Asia quota covers players from member countries of the Baseball Federation of Asia and Australian players.
Injury replacement: since 2024, if a foreign player suffers an injury needing six weeks or more of treatment, a club can place him on a rehabilitation list and sign a temporary replacement without using up one of its limited foreign player changes. The injured player cannot return for at least six weeks. When he comes back, the club must either convert the replacement into a permanent change, which uses one of its changes, or release him. Replacement costs are capped at US$100,000 per month. So when a club announces a replacement for a foreign pitcher with a six-week diagnosis, you can expect the original player to miss at least six weeks.
On Daily IL
Daily IL uses seven statuses: OUT, DOUBTFUL, QUESTIONABLE, PROBABLE, IL (injured list), SUSPENDED and RETURNED. A KBO player placed on the injured list is shown as IL. Players removed for an injury without an IL placement, or still on the roster but unlikely to play, are shown as OUT, DOUBTFUL and so on. Once a player is registered again, the status changes to RETURNED. If you know the removal date, the 10-day rule tells you the earliest possible return. Each status is explained on the status guide page.
Sources
- KBO press release – What’s new in the 2026 KBO League (Korean)
- Newsis – The KBO’s first injured list (Korean)
- Sports Kyunghyang – KBO board revisions, December 2020 (Korean)
- Star News – 2026 KBO rule revisions (Korean)
- OSEN – Asia quota confirmed for 2026 (Korean)
- News Seoul – KBO third executive committee meeting of 2026 (Korean)
- OSEN – Ahn Woo-jin injured list case (Korean)
- News Seoul – KBO introduces replacement foreign player system (Korean)
- KBO press release – Replacement foreign player system (Korean)
Rules can change from season to season and between competitions, so always check the latest official announcements from each league or competition.