NRL return to play skills test for injuries

[maz]

hi all!
I'm a yr 12 student doing an assessment on sports medicine, specifically NRL injuries. I need to know the most common injury that occurs in league and design a skill/physical test that indicates whether the player can return to play after the injury. Through my research I've been told corked thighs are the most common...I hope thats right!
Any help you could give me would be greatly appreciated.
Cheers
maz!

[injuryupdate]

Probably agree that cork thigh is most common injury overall, but players normally don't miss a game with this injury. Other common injuries you can analyse at:
http://www.injuryupdate.com.au/images/research/NRLinjuryrates.pdf

Fitness testing in rugby league for return to play is mainly functional. In other words, can they run and tackle at training in a similar fashion to what they would be required to do in a game?