Actually, I believe the pinch-hit HR was against the Yankees with two outs in the ninth that game where the Rays rallied to make the playoffs on the final day of the season. He also homered off Thornton last year, it was a 3-run shot and not in a pinch-hitting role.
Other than that, we're on the same side in this debate. I suppose Dan Johnson could help the Sox, but I wouldn't bank on it. He's never been good at the MLB level.