bbase,
Let me respond to the walk-on part of your question. (I'm don't see how a redshirt situation is applicable to this thread.)
For D1, D2, and some JCs, we can divide incoming freshmen or transfer players into four categories.
- a) players on athletic scholarship
- b) recruited and invited players without an athletic scholarship. This is a recruited or invited walk-on. (Sometimes a player is recruited--meaning, for example, more than one phone call from the college--but ultimately isn't invited to the team.)
- c) players who the coach is unaware of. A walk-on.
- d) players who were known to the coach but not recruited. A walk-on.
Obviously a) players are expected to make the team.
Some b) players are also locks to make the team, because there aren't enough athletic scholarships to make up an entire roster, but all the others also have a reasonable chance. A few schools limit the number of invited walk-ons so that all will make the team, but most bring in a larger group of invited walk-ons. The coaching staff believes that each of these players has the potential to make the team.
Perhaps a c) player could make the team, but I think it is very rare. As RJM suggests, it would be better for a player to have contacted the staff before arriving at school, and to have built a case for why he should be given an extended try-out.
99.99% of c) and d) players, regardless of school (perhaps D3 is different), have no chance of making the team. If the school offers try-outs, it will last perhaps 2 or 3 hours, and unless a player runs a 6.5 60 yard dash, or pitches at 90+ mph, he won't be noticed.