It was strange to us, too. I might have mis-spoken thinking it had to do with being a grad-transfer. I went back and looked, and this is what someone I trust had informed me about 2 years ago:
Athletic Scholarship Agreement (ASA) is only binding for the school and not the athlete (unlike an NCAA Letter of Intent).
And, since you can only sign a letter of intent once, Martinez would only have been able to sign an ASA with LSU. Ironically, after Martinez was released from LOI with Miss. State her senior year in high school, she was given her release. She then ended up signing an ASA with Texas, an official announcement of her addition was made, and she appeared on the Texas hoops roster. Weeks later she was removed the roster, and we read that she had signed (an ASA) with West Virginia. So, she obviously knows the rules very well by now . . .