Injury Replacements During Playoffs

I understand the in season need to cut off free agent acquisitions, but what about playoffs. We need to have the option to replace a player that has a long term injury with another player. 20% penalty should be imposed. In live baseball, when a player is injured, the team has the ability to recall a replacement player (usually between series). The coding should only allow for an injured player to be replaced. They would be off the team unless they were to replace another injured player.
I am in the playoffs now (semis) and have a starting OFer out until game 7 of the finals. Sure could use another active player.