The Painter question is legitimately whether it would be best for him to work on a few things in AAA like Abel did last year.
With Walker I don't think he'll ever be that good, but I also have doubts about him in a bullpen role. I suppose if he is bad in 2 more starts they'll have the license to send him down and let him refuse the assignment if he thinks another major league team would claim him.
The mistake would be a 6-man rotation. Why go from 1 weak spot every 5 starts to 2 out of 6? The schedule already provides off days so there are few 4-day rest starts. Given how we can easily use 4 relievers in any short start, I really like having an 8-man bullpen. It all could work out with injuries but Pop probably will be more useful from the bullpen than Walker. Not a huge difference and our lack of starting depth means the safe choice could still be Walker. This is not an obvious choice for DD and it will be interesting to see what he does.