The other four starters his senior year were Jerian Grant, Demetrius Jackson, Steve Vasturia, and Zach Auguste, so somebody had to have played the four. For sake of contrast, they played a Kentucky team in the elite eight that might have rolled out the tallest starting five in college basketball history, and they lost at the buzzer.
Duke started Matt Jones, Grayson Allen, Luke Kennard, and Marshall Plumlee alongside Ingram. The following year, they played Kennard predominantly at the four - with Allen, Jones, Frank Jackson, and Amile Jefferson - until Tatum returned from injury and then they played him there in pinches when Tatum returned.
Villanova played Josh Hart at the four a lot last season, Oregon went to the final four with Dillon Brooks sliding up a position for the injured Chris Boucher, and Xavier road a four guard lineup to the elite eight with their star point guard sidelined. Devin Robinson was 200 pounds soaking wet when Florida went to the elite eight last year.
I can probably name a lot of other examples, but my main point is that, with the way basketball is played today, it'd probably be optimal to play Larrier at the four under the best of circumstances. With the front court as depleted as it is, it's a no-brainer. I'm worried about rebounding, too, but the best way to limit offensive rebounds is often to keep the ball in front of you. The five is a far greater question mark for me.