Injuries can often be used as an excuse to skip out on a gym session but there is generally always going to be an option available for you to implement; to at the very least maintain strength when inhibited by injury.
Performing heavy lower body work can often prove difficult when carrying an injury to your upper body. You may be unable to bear any load on your shoulders to squat or push a sled or struggle to hold onto any weight to deadlift or kettlebell swing.
Sled drags/walks are perfect for removing any load on the upper body or spine. They can be used as a heavy strength building tool with high loads or a recovery/maintenance tool when using light loads.
Be sure to emphasise full extension through the hip, knee & ankle as well as driving your feet through the floor.