Versatility is great, but an above average SS or catcher doesn’t get moved around. This is especially true if they possess starter quality offensive skills. A well below average offensive player needs defensive versatility to stick in the majors. Unless Lewis shows himself to be below average as a SS without reasonable expectation for improvement, I would give him all the reps possible there. The other exception is the appearance of a better SS option. As of now that is not the case or likely in the foreseeable future.
Another possibility for improvement of the infield defense is to greatly upgrade the third base defense to help cover some range and arm concerns with Polanco. If that is the plan I can get behind a Lewis move to third.
You are describing past “Utility” definitions.
Super Utility is alive and well in this day and age.