Tarell Brown made a silly mistake on Sunday, and now he's got to pay.

The San Francisco cornerback wore a red undershirt instead of the 49ers designated undergarment color of white, and for that he received a $5,250 fine from the NFL.

We know all of this because Brown tweeted the letter he received from the league. The letter stated the reason for Brown's fine is as follows: "Rule 5 Section 4, Article 5(a) of the 2012 Official Playing Rules of the National Football League states that all members of the same team who wear approved undergarments with exposed necks or sleeves must wear the same color on a given day."

Brown's letter (and the photograph that he tweeted) contained login information for the league's secure website, and before it could be changed, Deadspin went on the website and took a screenshot for all to see.

Brown quickly took the photo down, and the NFL changed the information.

The former Texas star is not the first NFL player to tweet a photo of his fine, but he is the first to tweet the fine as well as his private login information.

(H/T to USA Today)

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