I know this is an old thread, I was wondering where the pain manifested. My son has been dealing with pain in hip/back region but closer to pelvis. not in the joint itself but a little higher up. I am thinking he has a slight sprain in the SI joint. He's 15, throws hard, mid 80s and slipped on wet grass long tossing about 6 weeks ago. He kept trying to play on it, but it just never seemed to heal. He can throw with no pain but only to a point, if he tries to really air it out he feels a sharp pain in that spot. xrays were negative and have only been dealing with a chiropractor, works with the Astros so knows his stuff but I do have a ortho apt in a few weeks in case it persists. we shut down baseball for now, lost summer unfortunately.