There have been a number of scientific studies done in scrum caps and whilst there is some disagreement most of the evidence points towards them having no affect or actually increasing the chances of concussion.
The mechanics of concussion as above are related to the effects of the brain hitting the inside of the skull.
Scrum caps increase the size of the impact zone and also give the wearer more confidence which can lead to increase in numbers of concussion.
Scrum caps do without doubt reduce the potential for cuts but not concussions it is generally agreed.
The best way would be to look at the mechanics of his run and impact, and look for improving technique.
He is a tall rangey player which will mean he will have larger areas exposed and to work on.
From a purely firm point of view though Isa and Faz need to be starting secondrows.
Greenwood had a great start to his Wigan career, however I’ve not been too impressed for much of his time at Wigan thus far.