Traditionally, college football rosters were built exclusively through direct recruiting of players from the high school ranks to join the roster. You know the structure: meet them at their schools, watch film, get them to visit, and eventually, pick a team.
The landscape of roster development and talent acquisition changed in 2019 when the NCAA implemented the Transfer Portal. This alternative path is a one-time, immediate eligibility (in most cases) chance for a player to leave their current team to go play for a different school. Some people called it Free Agency, but it’s not exactly that. But the Portal has given players much more free movement around the sport, and teams the ability to bolster their rosters with game-ready talent.