Should i get my mate to ask her for me?

this is girl and i have had a 'thing' going on for a bit now, but recently i dont know whats up with her, shes not the same with me anymore. i really like her and odnt wnat things to end so is it a good idea to get my friend to subtley try and find out whats up, or is that showing cowardliness on my part? also, what should i get him to ask; what quesitons are subtle but will be informative to me?