Youkilis not tanking would be a first. Hes a career .244/.351/.384 hitter after the ASB, and a career .306/.408/.472 hitter before it, and those splits were even more pronounced last year. He has completely fallen off the table offensively in the second half in both 2006 and 2007.
His power fades as the season goes on, and his strikes outs go way up. If this trend continues again this year then I see no reason why they would sign him to a long term deal. Especially if Lars Anderson continues to improve in the minors.