Swihart was a former top 20 catching prospect who was extremely hyped by the ESPN machine a few years back. He hasn't played much the last few years but is out of options and basically sitting on the end of the bench like a rule v guy. He wants out. He hasn't hit - he has a .234/.295/.320 career line at AAA - and he hasn't caught much over the last few years (65 games behind the plate the last two years).
Obviously, there is some upside since he was a former top 100 guy and the #2 catcher in the minors. He's a switch hitter. I don't think he'd cost much, if anything. His biggest problem is he'd need a 25 man roster spot. But he might be an upgrade over Wilson.
But Realmuto would be a nice upgrade too.