This is a perfect illustration of why, when people once upon a time suggested moving JPA to 1B, or wondering if the Mets would move d'Arnaud to 1B if he keeps getting hurt, it's never a good idea.
Even having a down year by his standards, Mauer would be right around top 10-15 offensively among catchers with his #s so far this year. But those same #s translated to 1B make him 30th in wOBA among 1Bs with at least 100 PAs to their name this season and no higher than 17th in any slash line category (including being 28th in OPS and like 34th of 38 in SLG)
Joe Mauer the catcher is a great offensive piece for a catcher. Joe Mauer the 1B would be good but not great. Joe Mauer the fading 1B is pretty bad.