The Red Sox DFA'd Lillibridge to make room for Carl Crawford's return (until his arm explodes). So, Cherington traded Kevin Youkilis for Zach Stewart and three weeks of fucking Brett Lillibridge. Good job, Ben.
Not that I loved the deal, but they weren't going to get anything more for Youk. Hell, the other deals on the table were "pay his whole salary, we'll take him off your hands" kind of deals.