Shouldn't there be a beginning trade deadline?

The drafts for various baseball pools was yesterday afternoon and already I received a trade proposal. Naturally I turned around and offered a couple in response.

Of course, this was the trade: Gary Sheffield and Travis Hoffman for Vladamir Guerrero and Fransisco Rodriguez.

Er, I don't think so! Sheffield was actually better than Guerrero last season in fantasy stats, but that doesn't mean he's expected to actually continue that. And Hoffman is a definite downgrade from K-Rod, who had 2 fewer saves with 40 fewer strikeouts.