Yes, from WPSOLR 14.6, you can.
How does it work ?
WooCommerce sort drop-down list contains a few default sort items. But, as you know, WPSOLR is able to sort by virtually any product custom field.
Just select the option “Replace WooCommerce drop-down list content with WPSOLR’s” in your WooCommerce pack, et voilà!
What are the benefits of replacing WooCommerce default sort items ?
You can, with WPSOLR, sort on any product custom field (if it is not a multi-valued field), without sacrificing performance.
– Attribute variations
– Distance (if the Geolocation pack is activated)
How to configure the sort items ?
Simply configure the sort items as usual, in WPSOLR configuration. And give each of them a sortable Solr type (string, or number, or date).
Set a default sort
Use WooCommerce settings->products->display menu to set the default sort..