It’s not only possible, it’s undisputed. He’s a terrible 1B man, but he’s a worse catcher, except he’s more awful at 1B, only he’s even worse at catcher, but…
Or if the first baseman isn’t at the bag, holding the runner. That’s the issue that makes defensive indifference most clear IMHO. Most runners of average speed can steal second easily if they can get the type of lead that would be allowed by not being held at first.
He’s poor in general. His throwing has always been bad - it’s much worse now than it used to be but he was never even average - but he’s also a mediocre catcher in most other areas.