Massachusetts may have a reputation as the bluest of Democratically blue states, but it is also resoundingly red — as in Red Sox nation. And President Barack Obama seemed to hit a nerve at a fundraiser in Boston on Monday night when he made a joke involving his favorite baseball team, the Chicago White Sox, at the expense of the suffering denizens of Fenway.

“Boston, I just want to say thank you for (Kevin) Youkilis,” Obama said at a fundraiser at Boston Symphony Hall, referring to the popular infielder, a fixture on two Boston World Series winning teams, who was traded from Boston to Chicago during the weekend.

The crowd, who had paid at least $250 per ticket, reacted to his comment with (friendly) boos.

But Obama continued: “I’m just saying. He’s going to have to change the color of his ‘sox,’” a comment greeted by more laughter and boos.

So Obama quickly backpedalled — perhaps like a first- or third-baseman (like Youkilis) chasing a popup — “I didn’t think I’d get any ‘boos’ out of here, but, I guess I shouldn’t have, I should not have brought up baseball. I understand. My mistake,” he said, to more boos.