The Ravens placed Kolar (sports hernia) on injured reserve Wednesday, Clifton Brown of the Ravens' official site reports.
Kolar underwent sports hernia surgery early in camp and will be unavailable to begin the regular season. However, the 23-year-old will be eligible to return after missing a minimum of four games, and he'll attempt to carve out a role behind Mark Andrews, Nick Boyle and Isaiah Likely once he's healthy.