I think this is a great deal, at the very least unlikely to come back to bite us.
But I am old enough to remember a pitcher named Russ Meyer. His career started off with the Cubs, and naturally, they traded him away (sold him?) just in time for him to get fairly good. But most of all, he was known as a "Cub Killer", having an outstanding record against the Cubs. So they got him back in a trade, and he stunk up Wrigley field for most of one season before they let him go.
But he should go on a hot streak, he might be able to drag the rest of the Cubs offense with him, kind of like Cespedes did for the Mets a few years ago.