From the MLS roster rules:
If a player suffers a season-ending injury, a club may place that injured player on the Season-Ending Injury List and receive roster relief (i.e., an open roster slot). Once placed on the Season-Ending Injury List, the injured player will not be eligible to play for the club in any remaining competition during that MLS season (including any exhibition games or tournaments, including but not limited to: Leagues Cup, Campeones Cup, CONCACAF Champions Cup, Canadian Championship and Lamar Hunt U.S. Open Cup.
A club may replace an injured player that is on the Season-Ending Injury List with a replacement player in accordance with parameters below.
The club will remain responsible for the injured player's full Salary Budget Charge. Clubs are only able to receive Salary Budget relief (paid out of the club's own pocket) for a season-ending injury replacement under the following parameters:
- The injured player must be formally placed on the Season-Ending Injury List prior to the opening of the Secondary Transfer Window. The replacement player must be declared as such when being added to the club’s roster and must be acquired by the Roster Freeze date (Sept. 12, 2025) and after the related injury occurred.
- The Salary Budget Charge of the replacement player may not be more than the player who suffered the season-ending injury. If the injured player placed on the Season-Ending Injury List is a Designated Player, the club may replace such player with a Designated Player, provided that his Salary Budget Charge is not more than the player he is replacing. The replacement player’s charge will not be charged against the Club Salary Budget.
- Clubs will only be allowed to sign one such replacement player per MLS league season.