College football's post-spring SP+ rankings and takeaways

Two-time defending champion Georgia takes the top spot in the SP+ preseason projections. Kirby Lee/USA TODAY Sports

The transfer portal is slowing down, media days are around the corner and with all due respect to Week 0 -- I love it dearly, just as much as all the other weeks -- we're officially 100 days from Sept. 2, the first real Saturday of the 2023 college football season.

It seems like a pretty good time, then, to get up to date on the numbers. Since February's initial 2023 SP+ release, we've seen a number of transfers and big moves, and I've been able to better update returning production figures to account for teams' official roster releases. (Not many had released full rosters in early February.) We haven't seen much movement at the very top of the rankings, but there's plenty to talk about.

A quick reminder: Preseason projections are based on three factors.

1. Returning production. The returning production numbers are based on rosters I have updated as much as possible to account for transfers and attrition. The combination of last year's SP+ ratings and adjustments based on returning production makes up more than half the projections formula.

2. Recent recruiting. This piece informs us of the caliber of a team's potential replacements (and/or new stars) in the lineup. It is determined by the past few years of recruiting rankings in diminishing order (meaning the most recent class carries the most weight). This is also impacted by the recruiting rankings of incoming transfers, an acknowledgment that the art of roster management is now heavily dictated by the transfer portal. This piece makes up about one-third of the projections formula.

3. Recent history. Using a sliver of information from previous seasons (two to four years ago) gives us a good measure of overall program health. It stands to reason that a team that has played well for one year is less likely to duplicate that effort than a team that has been good for years on end (and vice versa), right?

(One other reminder: SP+ is a tempo- and opponent-adjusted measure of college football efficiency. It is a predictive measure of the most sustainable and predictable aspects of football, not a résumé ranking, and along those same lines, these projections aren't intended to be a guess at what the AP Top 25 will look like at the end of the year. These are simply early offseason power rankings based on the information we have been able to gather to date.)

Here are the full, updated rankings: