Should I trade Pujols, and if so for what in a Yahoo-Standard 10-man league?

I wouldn't. But if you do, you should look for some power in return along with a new closer or catcher. Mauer seems to be headed for a very disappointing season and Avila is unproven for the most part. Brandon League won't be a closer all season. For power in return, I'd go for a player like Ryan Braun. In addition, you could get a top tier closer or maybe even a top level SP. Maybe try and pair Pujols and League together in a deal.