If I signed up for RASP in AIT, but injured my ankle and am unsure if it will hold up, will I be able to reapply for RASP when I'm healed?

You can't start RASP on profile. Talk to your medical team about wanting to go to RASP and they should ensure you have an appropriate profile that will allow you to recover fully. Temporary medical conditions do not permanently disqualify you from trying RASP. My understanding of a DEC statement is that it is for formally stating your intent not to reenlist, and it is not something IET soldiers can or should do. I recommend healing up and getting in great shape so you can do a great job at RASP.

PV2 Egerer, since you are in AIT you can and should ask your Airborne and Ranger Assessment and Selection Program (RASP) Liaison Officers (LNOs). They exist and are accessible; they will come to you if needed or you can ask your command how to contact them (check your installations directory on the web too bc they will likely be listed with a phone number). As for the process of how this works for AIT students in your situation, the RASP LNOs are the people who will process AIT Declination Statements with the Military Personnel Division (MPD) on your installation. In turn, MPD will update the Army Training Requirements and Resource System (ATRRS) within 24 hours to cancel your RASP date and will then generate new assignment instructions (probably to your first duty station). Your AIT Declination Statement will state that you declined RASP for medical reasons (not bc of an unwillingness to attend). Depending on your MOS requirements, and the type of unit you are assigned to, you can have an opportunity to apply for RASP again. RASP is a physically and mentally intense 8 weeks and if you're not confident 100% (and then some) in the readiness of your ankle and your overall fitness, the extreme conditions of RASP could leave your ankle far worse.