There's only a couple of choices on how to look at this. You can accept that he is learning a new position on the fly and will make tough mistakes. I advocated for his move to first in the offseason so we wouldn't be going through this learning curve in August. Had they committed to this, Bell likely doesn't get signed and we save money which could have put into the bullepen at the beginning of the season. Shelton stayed the course to see how the players would react before making wholesale changes. Lewis is a professional and knows he messed up and will learn.
The other option is to fire him into the sun, or the baseball equivalent, DFA him and move on. I guess you could send him to St. Paul. That option almost automatically leads to a combo of Bell, Caratini, and Jackson playing 1B. Clemens is not a permanent option there as they need his flexibility to plug holes elsewhere in the lineup. Idk if it's true, but I would bet that Lewis is still a better defensive option than the combination of Bell, Caratini, and Jackson at 1B.