Nike released an advertisement campaign Sept. 3 featuring embattled former NFL quarterback Colin Kaepernick. Kaepernick started kneeling during the national anthem during the 2016 season to bring attention to racial injustice. He has not played in the NFL since that season.
>>Related: WATCH: Colin Kaepernick stars in Nike's 'Just Do It' 30th anniversary commercial
Although the company has faced some backlash, online sales for Nike went up 31 percent after the campaign launched.
Zahn never referenced the ad campaign in his letter.
A spokesperson with the city did not comment to WVUE about the directive.
Councilman Gregory Carroll called the letter disturbing.
"I was not made aware of this decision beforehand and it is in direct contradiction of what I stand for," Carroll said in a statement posted on Facebook. "I will meet with the mayor and other council members in an effort to rescind this directive."
WATCH: Nike Releases First "Just Do It" Commercial Featuring Colin Kaepernick