Arizona re-adding four-star guard commit Brandon Williams over the weekend propelled a recruiting class without a single player lined up a month ago to No. 21, per 247Sports national rankings.

The Wildcats’ resurgence on the recruiting trail amid the tumult of an ongoing FBI probe offers some renewed optimism for a program that was facing bleak uncertainty. And a brighter outlook for Arizona reflects a generally improved forecast for Pac-12 basketball in general, thanks to the Class of 2018.

Pac-12 basketball had a 2017-18 season that can be most accurately described as a dumpster fire. The conference sent three teams to the NCAA Tournament, two to the First Four, and came away with zero wins.

Any time your conference tournament runner-up, which also finished the regular season in second place, fails to make the Dance, you’ve had a bad year.

Fortunes can turn quickly in basketball, however. Any program is one great recruiting class away from dramatic improvement; and currently, no conference is recruiting collectively as well as Pac-12 basketball.

Arizona’s move to No. 21 gives the league five of the top 21 classes of 2018 thus far, matching the SEC for most, with one more than the Big Ten; two more than the ACC; and three more than the Big East or Big 12. Three of the nation’s top 10 classes — Oregon, UCLA and Arizona State — hail in the West.

On the other end of Arizona, Stanford, Washington and Cal check in at Nos. 28 to 36. Pac-12 basketball accounts for exactly one-quarter of the top 36 signing classes of 2018 to date.

In Washington’s case, the influx of some new talent joins a solid corps of returners under 2017-18 Pac-12 Coach of the Year, Mike Hopkins. I’m high on the 2018-’19 Huskies, including them in my initial Athlon Sports Top 25.

Cal endured a brutal first year under coach Wyking Jones, but the addition of excellent recruiting assistant coach David Grace last month appears to be paying immediate dividends. The Golden Bears landed four-star 2019 prospect Charles Smith IV last week, laying the foundation for Cal’s class next year.

How losing Grace impacts UCLA on the recruiting trail in the coming years will be fascinating, and perhaps have direct correlation to the program’s direction. In the meantime, though, UCLA’s Top 10 2018 signing class is reminiscent of the 2016 crop that transformed a team out of the NCAA Tournament field into a 30-game winner.

Five-star prospect Moses Brown and high 4-star Shareef O’Neal could very well give the Bruins one of the most talented front courts in the nation.

UCLA, like fellow 2018 recruiting winner Oregon, returns enough of a veteran foundation to combine with an outstanding group of newcomers to project big things in 2018-19. The Bruins and Ducks look like the strongest contenders for the Pac-12 basketball title ahead of the season, but it’s not a guarantee.

More certain is that the Pac should be dramatically improved next season.