Sanchez will be the backup backstop to Adley Rutschman, but should see playing time against left-handed pitching as a designated hitter as well. His position makes him a bit more appealing in fantasy than any other, but Sanchez would need an injury to Rutschman to be a truly viable starting catcher in fantasy.
The Orioles wanted to upgrade from free agent James McCann as their backup catcher, particularly since Adley Rutschman has been so much more productive as a DH than he has been while behind the plate. Rutschman will still do the bulk of the catching, of course, but Sanchez will add some more offense and can hold down the fort as a starting catcher if Rutschman ever goes down.