Can I be demotiondue toan injury?

Texas is an at-will employment state-- which means that either side can back out of the employment relationship at anytime.  The exception for employers, however, is that they cannot do so for an impermissible purpose.  Employers cannot discriminate against persons who suffer from a disability, who are out on leave under the Family Medical Leave Act, or who have filed a worker's comp claim.  Since you don't know if your injury is work related, the best answer to your question is "it depends."  IF your injury is work related, and he is temporarily changing you job duties as an accommodation-- then that's okay.  If he is demoting you for a work related injury, then it would be considered worker's comp retaliation-- big no no-- and you could file a complaint through the Texas Worker's Comp Commission or a private attorney.  IF your injury is going to require you to be off for an extended period of time and you were/are in the process of applying for FMLA, then your boss could be subject to an FMLA violation.  FMLA causes of action, however, are limited to employers of a certain size.  IF your injury is due to or the beginning of a disability, then you may be able to file for ADA protection.  If your boss is changing your duties to accommodate a disability, then that is acceptable.  Before anyone can help you figure out what you can do about the situation, you really need to figure out the cause of the injury and how long it will be a problem.  From there, apply for FMLA or ADA or Worker's Comp protection (you may qualify for more than one) and get the paperwork to perfect your claim.  You may also want to consult with an employment law or personal injury attorney to see if other options are available depending on the more specific details of your injury and subsequent condition.