according to the link provided, they cannot oversign. If a player is drafted, they have to wait till he is signed before they replace him, which leaves them WAY late to the recruiting party when it comes to getting a replacement.
The link bemoaned the competitive disadvantage it gives BiG teams, but I like that they are not allowed to oversign like at some of the other schools. I have known some talented kids who were lured to some big name baseball schools, only to rot on the bench, or not play at all due to oversigning- something the RC's neglect to mention when they are attracting the kids to the school.