The last day to enroll in the spring semester is today. So, if you're not enrolled today, you cannot participate in spring practice.
However, you can still enroll for either summer session or for fall later this year and be on the fall roster.
So spring ball participants need to be enrolled by today. Can still have roster additions for this season enroll later in the year, however. Those will be any kids who sign in the traditional signing day in February, plus any transfers between now and summer.