Tarrel BrownThe remainder of the letter explains the process for appealing the fine, but that's the part I'm most interested in.
c/o San Francisco 49ers
4949 Centennial Boulevard
Santa Clara, CA 95054
During the Detroit Lions-San Francisco 49ers game on September 16, 2012, you were in violation of NFL Uniform and Equipment Rules.
Specifically, you wore red undergarment sleeves. Your team designated undergarment color is white. 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.
NFL policy on uniforms and equipment and the "On Field" program is disseminated to players through playbook inserts, locker-room posters, and training-camp videos. In accordance with the document entitled "2012 GAME-RELATED DISCIPLINE", which was among the playbook materials distributed to you earlier this season, the League is imposing on you a fine of $5,250.
You can see that the other 49ers were wearing their League- and team-approved white undershirts in that game:
I do with the Packers would make a change to theirs, though. The contrasting undershirts have long bothered me.
Contrasting undershirts needlessly clutter up the uniform, and matching them to the jersey color would at least give a hint of the old long-sleeve aesthetic.
Even if the Packers won't incorporate the compression shirts into their uniform design, at least the team could ensure that they don't work against that design. It would look something like this photo of AJ Hawk at training camp a couple years ago: