Stats show Duke is still good enough to reach the Final Four without Caleb Foster, but there's a catch

Duke avenged its February loss to North Carolina by beating the Tar Heels in Durham on Saturday, but it came at a steep cost. In the process, Jon Scheyer’s Blue Devils lost their starting point guard, junior Caleb Foster, to a fracture in his right foot that, unless they reach the Final Four, is almost certainly season-ending. 

Duke is still favored to win the ACC Tournament and is a lock for a No. 1 seed in the NCAA Tournament, if not the No. 1 overall seed in the Big Dance. That will give Scheyer a favorable path to get back to the Final Four, and though he doesn’t have the deepest roster in the country, the numbers say that the Blue Devils still have enough to make the final four without Foster on the floor. 

Duke’s numbers are better with Caleb Foster off the floor

Foster hasn’t missed any games yet this year, so Duke will get its first taste of playing without its 6-foot-5 point guard in the ACC Tournament this week. That will thrust freshman Cayden Boozer into the starting lineup for just the fifth-time this season, and with starting center Patrick Ngongba also set to miss this week’s action in Charlotte with foot soreness, Scheyer will have to dust off Cameron Sheffield and Jack Scott for depth, especially with Rice transfer Ifeanyi Ufockukwu out for the season with an injury he suffered back in December. 

While Duke doesn’t have any experience with Foster watching from the sidelines for an entire game this season, the Blue Devils have played 450 minutes with Foster on the bench, and those minutes have gone quite well. 

ON/OFF numbers require context, especially for a starter like Foster, who often plays in Duke’s closing lineup against its best competition. He’ll be out there for the toughest moments, and therefore, the net rating with him on the floor vs. off it may not necessarily be reflective of his value. Still, by real adjusted plus/minus, Cayden Boozer is much better than Foster at 6.9 to 4.4, and by win shares per 40 minutes, Boozer is at 0.17 to Foster’s 0.16. Having them both would be better, of course, but there’s a real argument that Duke is better with Cayden Boozer at point guard than with Foster, especially defensively.

Foster is shooting 40 percent from three again after a serious sophomore slump, and the additional spacing that provides, especially compared to Cayden Boozer’s 29 percent, is reflected in the offensive numbers. But, for Foster’s size, length, and switchability as a point of attack defender who can credibly handle 1-3, Duke’s defensive numbers are meaningfully improved with him off the floor, even if that improvement is from the 96th percentile to the 100th (per CBBanalytics.com). 

Duke has 15 different lineup combinations that have played at least 20 minutes, or one full half, together this season. Of those 15, the best two by net rating don’t include Foster. In fact, of the eight linueps that have played at least 20 minutes and have a net rating of +40 or better, Foster is included in just one of them. Cayden Boozer is in the other seven, including one without his brother and presumptive national player of the year, Cameron Boozer. 

But Duke isn't better off without Caleb Foster

This isn’t to minimize Foster’s impact, because Duke’s most prevalent lineup this year is its typical starting five: Foster, Isaiah Evans, Dame Sarr, Cameron Boozer, and Patrick Ngongba, and that group has a +44.8 net rating. It’s to say that Duke’s new starting five, especially once Ngongba is back for March Madness, will be just as good if not better. Where the issue will come is the lack of depth. 

Against North Carolina, Duke cut its rotation to just seven players once Foster went down, forcing Cameron Boozer to play 38 minutes, Sarr to log 34, Brown to play 30, and Cayden Boozer to play 29. That’s going to be difficult to sustain as Duke attempts to win three games in three days, including a likely rematch with North Carolina in the ACC Tournament semifinals on Friday. 

With Ngongba back for the Big Dance, though, Duke should be fine navigating the first weekend of the NCAA Tournament, and is still a good bet to emerge from the second weekend unscathed.