I'm not sure how relevant Santini being able to go or not is to this season.
Sure it will help if he's ready, but If not I don't think it is a big deal. I'm honestly more concerned about the left side depth and the fact that Merrill and Moore are the two best defenders after Greene on the Left side.
I'm going to be a little abrasive now, but hear me out...Larsson never proved he could anchor a pairing by himself, he hasn't provided much offense throughout his career and he was the worst skating regular defenseman we had on our team.
If you have bought into the "Fast, Attacking, Supportive" mantra, Larsson was the perfect piece to let go, he wasn't much of any of that. Who replaces those minutes isn't really important...Fayne has had them, Salvador has had them, Severson has had them for a short time too and has done very well with them. We still need to address the defesne...But the minutes on Greene's right side is the least of our worries.