Joba is a very good pitcher, but he's not without weaknesses. Watch Joba in the second, fifth, and (if he makes it that far) seventh innings tonight. For whatever reason, that's where he's been having trouble. Pitches 26-50 are Boston's best window of opportunity.
In nine starts Joba has earned only a 1-1 record. He's started only three road games, and only one AL road game. He pitched in Toronto, losing 5-0, allowing 3 ER in 6.2 IP.
In 57 fly balls allowed, Joba has only yielded 3 HR. That's low, and that's luck: he should've yielded six-odd, and that would've substantially jacked up his ERA.
Boston is 36-11 at home this season. Josh Beckett is pitching. Boston is 8-2 in Beckett's last 10 home starts.