Cain roughed up in potential final rehab start

Giants pitcher Matt Cain leaves the game after a tough start and is placed on the 15-day DL with a hamstring strainIf Matt Cain's outing Friday night doesn't prompt the Giants to think twice about installing him in their starting rotation next week, it'll at least leave the team hoping for instant and vast improvement.

Cain was hit hard and often in Lancaster, Calif., where he pitched for Class A Advanced San Jose in what was intended to be his final Minor League injury rehabilitation start before facing the Red Sox on Wednesday.

But Cain's performance, in which he allowed nine earned runs and 10 hits in four innings, will at least cause the Giants to wonder what happened. Cain, who's…