How good can Cal star Ivan Rabb be?

The college basketball season isn't far off. It’s time to start looking at the important questions that will shape the 2016-17 season.

Fourteen months ago, California Golden Bears strength coach Nicodemus Christopher tweeted before-and-after shots of then-Cal freshman Ivan Rabb. The "before" showed Rabb in late June, just after he arrived on campus for summer workouts; the "after" captured him just six weeks later.

It was a Steve Rogers-to-Captain America-esque transformation -- enough to make any reasonable college basketball fan step back and ponder. Just how much talent -- skills, sure, but also just pure physical gifts -- did Rabb really possess? How much bigger, and better, could he get? And what would those answers mean for the Bears?

A year later, one of the great surprises of the 2016-17 season is that this exact line of inquiry remains as relevant as ever. In the spring, Rabb eschewed a likely NBA draft lottery slot in favor of a return for his sophomore season. And so, a year later, we again find ourselves wondering: Just how good can Ivan Rabb be?

In large part, this reprisal is worth asking of any young player with an obvious NBA future. Rabb was the eighth-ranked player in the Class of 2015, a five-star McDonald's All-American and Oakland, California, native. His decision -- followed a few months later by the unexpected commitment of Georgia native Jaylen Brown -- augured a huge year-over-year rise in expectations in just the second year of coach Cuonzo Martin's tenure. In May, all seven players ranked higher than Rabb in the Class of 2015 left for the NBA after just one season. Among them were Kentucky's Skal Labissiere and Kansas' Cheick Diallo; both struggled (for various reasons) in their lone college seasons.

Rabb, meanwhile, was excellent throughout. A 6-foot-11 forward asked to play a true center role in his first college season, he shot 61.5 percent from the field, grabbed 11.2 percent of available offensive rebounds and 21.3 percent on the defensive end, and he drew five fouls for every 40 minutes he was on the floor. His 124.8 offensive rating was a team best, all while shouldering every post-up opportunity Martin threw his way. Fifty-seven percent of Cal's post plays ran through Rabb, per Synergy scouting data, and he averaged .87 points per play -- not great, necessarily, but still pretty darn good.

All of which is to say: Rabb could be in the NBA right now, if he so preferred. His return was not driven by some weakness-exposing letdown of a season; he didn't plummet out of first-round projections by March. He is not a sophomore against his will. Instead, as he told SI.com's Brian Hamilton this summer, he just didn't see the need to go to the NBA quite yet. Nothing more, nothing less. Given how rare decisions like Rabb's are (at least for players as good as Rabb) and how infrequently college basketball fans get to see the tangible development of surefire lottery picks, excitement is the only rational response.

This would be true if Rabb were returning to a similar team as the one he joined last season. He is not. Not even close. And that might be the most exciting bit of all.

The 2015-16 Cal Bears were hardly a disappointment, either: Martin incorporated two stud freshmen alongside a veteran, scoring-oriented backcourt. And though it took a couple of months, by Dec. 22 -- when Cal swarmed Virginia's previously unstoppable offense in Charlottesville en route to a 63-62 overtime loss -- the potential was clear. Midway through Pac-12 play, Martin's team hit its stride and entered the NCAA tournament looking like one of the hottest, most dangerous teams in the country. Their first-round loss to a good Hawaii team was preceded by some truly terrible timing, on the court (see: injuries to Jabari Bird and Tyrone Wallace) and off the court (see: this), but the overall season was an undeniable success.

It was also tantalizing -- and not in the positive sense, either.

For all of Cal's defensive progress throughout the season, its offense never quite got there, in large part because Martin's other elite freshman -- for all of his obvious talent -- often hurt as much as he helped. Brown, the Boston Celtics' No. 3 overall choice in June's NBA draft, finished the season with a 95.4 offensive rating. He shot 48 percent from inside the arc and 29 percent beyond it, and he shot a lot -- accounting for 31.2 percent of Cal's possessions and 28.7 percent of its shots, while turning the ball over on 21.0 percent of his trips. Even the 6-foot-7 wing's best trait -- muscling his way to the foul line -- was mildly undercut by his 65.4 percent free throw shooting.

Wallace, for his part, gobbled up 27.9 and 27.0 percent of the Bears' possessions and shots but was no more accurate than Brown. All the while, Cal's three efficient starters -- Jordan Mathews, Bird and Rabb -- were secondary options, at best. (And, sure, perhaps they would have been less efficient with more volume ... but still.)

Why is this exciting? Because Rabb is the only starter remaining. A huge swath of possessions and shots that went to Brown and Wallace (among others) will now, almost certainly, come Rabb's way. Presumably, Martin will grant him far greater flexibility in how he approaches those touches -- more post-ups, sure, but also wing isolations, mid-posts, elbow catches, pick-and-rolls, you name it.

Thanks to both preference and necessity, Rabb in his sophomore year will have the touches and the freedom to truly display his skills. What is the ceiling for a scenario like that? Pac-12 player of the year? All-American? Higher? How much will California need from him? How good can he be?

One can't help but wonder.