Hopefully this isn't too bad of a sprain/tear. I'm not sure how bad the teres major rehab is but I tore my left shoulder's teres minor about a decade ago and it wasn't fun. It took forever to heal up and I'm not sure if it ever got back to 100% of before it. My doctor did say that the minor was one of the worse rotator cuff muscles to hurt and the hardest one. So I'm hoping my case was worse than Merrill's.