Teams do not choose to place players on SOIR. If a player on a 2-way contract that was on the NHL roster for less than 50 games played in the previous season is injured prior to the start of the season, they are automatically on SOIR. The SOIR cap hit calculation = No. of days on roster last season divided by total season days x cap hit.  Therefore, if a SOIR player was not on the roster during the previous season, they carry a $0 cap hit while injured.

For more information, check out https://puckpedia.com/salary-cap/SOIR