https://collegefootballtalk.nbcsports.com/2015/01/17/cost-of-attendance-multi-year-scholarships-approved/
Unless that has changed, scholarships can’t be pulled for athletic reasons.
Having a private conversation with a recruit about a one-year tryout then manufacturing a non-athletic reason for a non-renewal if it doesn’t work out violates that rule. Further, it sends a messag to future recruits that you don’t fulfill your end of the bargain or will look for loopholes to get out of your commitment to them if things don’t play out as planned.