On Friday, Trump tweeted, "What was Nike thinking?"
During Thursday's NFL season opener between the Philadelphia Eagles and Atlanta Falcons, a Nike commercial narrated by Kaepernick aired.
The ad featured the tagline, "It's only crazy until you do it. Just do it."
In an interview with Vince Coglianese and Saagar Enjeti of the Daily Caller on Tuesday, Trump said, "I think it's a terrible message," regarding Nike's partnership with Kaepernick.
Trump then tweeted Wednesday about those who were protesting Nike's decision to use Kaepernick as a spokesperson:
Donald J. Trump @realDonaldTrump
Just like the NFL, whose ratings have gone WAY DOWN, Nike is getting absolutely killed with anger and boycotts. I wonder if they had any idea that it would be this way? As far as the NFL is concerned, I just find it hard to watch, and always will, until they stand for the FLAG!
The president has long been outspoken against Kaepernick. The former NFL signal-caller became the first player to protest against social injustice and racial inequality by sitting and then kneeling during the playing of the national anthem before games in the 2016 preseason.
Since parting ways with the Niners at the conclusion of the 2016 NFL campaign, Kaepernick has gone unsigned.