Because if you remove him the OLB group looks rough. As a contender you want better quality on the edge than that group minus Von. And much of the reason they don't look good enough is due to not being able to trust Lewis as well as losing Oko who is a really solid rotation piece.
But I'm looking forward to seeing what Garrett can do with a full year of pro training. Hopefully he can stay out of McVay's doghouse, seems to me at least that the whole COVID thing got him off on the wrong foot with the team.