Henson was on the wrong end of a late hit by Deacon Manu in Saturday's friendly with the Llanelli Scarlets.
John Taylor, managing director of London Welsh, said: "We're quite upset with what happened and it certainly wasn't what Gavin needed.
"I haven't seen the video yet and don't want to say too much. We will have a look at it at the beginning of the week and speak to the Scarlets if necessary.
"We will deal with it internally between the two clubs."
Henson is expected to be out of action for six weeks following the incident.