http://www.baseballmusings.com/cgi-bin/LineupAnalysis.py?Player0=Pedroia&OBA0=+0.376&Slug0=+0.437&Player1=Youkilis&OBA1=+0.424&Slug1=+0.564&Player2=Bay&OBA2=+0.382&Slug2=+0.508&Player3=Drew&OBA3=+0.371&Slug3=+0.446&Player4=Lowell&OBA4=+0.341&Slug4=+0.495&Player5=Martinez&OBA5=+0.363&Slug5=+0.461&Player6=Ellsbury&OBA6=+0.348&Slug6=+0.406&Player7=Kotchman&OBA7=+0.354&Slug7=+0.413&Player8=Green&OBA8=+0.302&Slug8=+0.376&Model=1
According to this lineup simulator, an optimum Red Sox lineup can be expected to score up to 5.7 runs per game. They use OBP and SLG, which have the highest correlation with runs scored.
Adding Varitek and Ortiz cuts the production by .2 runs per game. Given that Tito has a fondness for batting Ortiz fifth, or even sixth, it is obvious what the Red Sox need to do if they want to score more runs to compensate for their lack of pitching.
Bench Papi. Bench Varitek.