Clausen has since deleted the tweet with the photo of the “Catholics vs. Cousins” shirt, which used those names to describe the Catholic university in Indiana and the inbreeding stereotype of the Deep South.
“I'm sorry if I offended anyone by posting that shirt, I didn't mean anything by it at all...Looking forward to a great game in Miami!” Clausen tweeted, referring to the Jan. 7 BCS National Championship between the Fighting Irish and the Crimson Tide.
Some Twitter users believed Clausen had the T-shirt especially made for him, but the Carolina Panthers quarterback said that’s not the case.
“The shirt was sent to me! I was saying THANK YOU #calmdownpeople,” Clausen wrote to his more than 45,000 Twitter followers.
Sports Illustrated writer Steward Mandel was among those on Twitter who condemned Clausen for the T-shirt.
“Jimmy Clausen, determined to remain unpopular even after college,” Mandel said, including a link to a photo of the T-shirt.
Twitter user @CaptainAnnoying also chimed in, writing, “Like Jimmy Clausen's 'Catholics vs. Cousins' T-shirt? Here's a shirt commemorating all of Jimmy's significant wins” -- a link to a plain white T-shirt from the Gap.
Others weren't so bothered by the shirt.
“Wait, is the outrage real against Jimmy Clausen for a shirt that says ‘Catholics vs. Cousins?’” wrote Twitter user Jeremy Hiler.