Obviously main prospect that can really throw things in a tizzy is Shabazz Muhammad. The nation's No. 1 player, Muhammad picking UCLA, Kentucky, or even Duke could make things very interesting for the Wildcats. Now Arizona technically could get a visit from Muhammad, but there is almost no chance he ends up playing his college ball in Tucson.
With that you can look at the scenario for Kentucky, the team most likely to be able to pass up Arizona. Currently Kentucky has three commitments, their top rated being Archie Goodwin and their lowest rated being Willie Cauley.
This three man class is the No. 2 class in the country currently. If Muhammad were to join Kentucky, than UK's four-man class would clearly be enough to pass up Arizona. However where it gets real interesting is if UK doesn't land Muhammad, but lands No. 9 prospect Anthony Bennett.
If UK were to close out their four-man class with Bennett, than both Kentucky and Arizona would have three five-star prospects and a four-star right outside the top 25. Really it would be too tough to call right now, but that might put Kentucky ahead of Arizona.
Also Kentucky still has Jarnell Stokes, Amile Jefferson, and Devonta Pollard left out there. Landing any two of those three would be enough to push the UK class above Arizona, so as you can see the Wildcats still have a great chance one way or another to finish with the top class even if they don't land Muhammad.
For the UCLA Bruins to bring in the top class it is pretty simple what has to happen. First, and most importantly, UCLA will need to land Muhammad. Most consider UCLA the team to beat for Muhammad right now, so that piece at least seems fairly likely. Muhammad plus Kyle Anderson would give UCLA two top-five commitments.
Also UCLA would need to add Tony Parker who is uncommitted, and seriously considering the Bruins. Adding Parker along with Muhammad would mean that UCLA's top three players would all compare favorably with Arizona's top three, and while Arizona would have the edge at the fourth player, and it would be very close, that likely would give the Bruins the No. 1 position overall.
If you are looking for an under the radar team who could surprise everybody and make a run to the No. 1 spot it would be Texas. The Longhorns are bringing in a huge class, both in terms of numbers and size of recruits, and they aren't done yet.
Currently Texas has five commitments headed by Cameron Ridley, the No. 6 overall player. Yet the Longhorns are still heavily involved with Devonta Pollard and Andrew White, and then also will be seriously involved with Ricardo Gathers.
Now Texas would have to get real creative with the numbers in order to make this work, but say they land Pollard and Gathers, that would probably be enough to put the Longhorns over the top and give them the No. 1 class with what would be a ridiculously good seven man class.
Those are probably the only teams that can pass Arizona right now. Schools such as Indiana, North Carolina, Michigan State, and Michigan don't seem to have any serious targets remaining in 2012, so they won't be moving up barring all of their commitments having unforeseen incredible senior seasons that move them up in the rankings.
However schools such as Duke, with Parker and Muhammad, NC State with White and Jefferson, and Memphis with Stokes and Parker could all possible make a run to a top three position if things break right for them.
Right now it is looking fairly safe for Arizona, but the Wildcats, who it should be noted are seriously involved with four-star prospect Amedeo Della Valle, are going to have to hold off some late charges to stay with the No. 1 class.