How good does the Maple Leafs backup have to be?

This trend is a major concern for TOR. They've never been known for playing tough defense but their trend of late has them as perhaps the NHL's worst. It's too much to ask of Andersen long-term and it's clearly too much to ask of any available back-up. pic.twitter.com/lfKubISgzG

I saw this, and couldn’t argue with the conclusion. So, I said to myself: Just how good a backup would you need on this team, not just lately when the defending is just horrible from the entire team, but overall this season?