USC fans weren't necessarily tracking quarterback Caleb Williams' initial recruitment out of Gonzaga High School in Washington, D.C., but they were certainly paying full attention to every move of his transfer portal experience, which now ultimately brings him to Los Angeles as the new face of the Trojans.

Williams made the widely-expected announcement Tuesday, and for a closer look at what makes this such a huge addition for USC, we bring in Rivals national recruiting director Adam Gorney to break down Williams' evolution as a top QB prospect and how he fits in with the Trojans.

What made Caleb Williams such a highly-ranked prospect coming out of high school in the 2021 class, as the No. 1 dual-threat QB and No. 6 overall national recruit?

Gorney: "After seeing him at Oklahoma perform the way he did, probably not high enough. Just an incredible decision-maker. He has all the arm talent in the world, so that's not of question, but quarterback is so important when it comes to decision-making and where he puts the ball, and that has been proven to be at the elite level. It was probably a very difficult decision, even though Spencer Rattler was struggling and had kind of lost his mojo a little bit, to put Caleb Williams in the game, but once they did at Oklahoma that really sparked that offense. He did a phenomenal job with the team and he basically displaced another five-star quarterback with the Sooners. And I don't think anybody regrets that decision now. He's a great decision-maker, he is definitely a dual-threat guy that can get out. I think we saw a lot of those runs during his time at Oklahoma and I think that should continue at USC."