There are two categories of players:

Everyone who appeared in at least wine game in 2021 should be healed and available for challenge games through mid February when the 2022 NFL data will be ready.

Players who missed the entire 2021 season will not be available. Since the simulations are driven by 2021 NFL data, there is nothing available to use to simulate them in the game. You’re pretty much stuck hoping they will bounce back in 2022.