Colin Kaepernick’s collusion case against NFL owners will argue that his continued unemployment is at least partially the fault of President Donald Trump, CBS Sports’ Jason La Canfora reports.

Kaepernick intends to argue that Trump, on Twitter and in public speeches, influenced NFL owners against signing Kaepernick, according to the report.

Trump has repeatedly attacked NFL players in recent weeks for protesting during the national anthem, even sending Vice President Mike Pence to Indianapolis for a premeditated performance where he walked out of the Colts-49ers game after San Francisco players knelt during the anthem. Trump has also mentioned Kaepernick specifically at least one time, referring to him as “your San Francisco quarterback—I’m sure nobody’s ever heard of him.”

“There was an article today, it was reported, that NFL owners don’t want to pick him up because they don’t want to get a nasty tweet from Donald Trump,” Trump said at a rally in Kentucky in March. “I said, ‘If I remember that one I’m gonna report it to the people of Kentucky—because they like it when people actually stand for the American flag.”

Trump no doubt has the ear of NFL owners. The day before the Kentucky rally, Patriots owner Robert Kraft was on Air Force One with Trump. Trump also tweeted last month that he had spoken with Cowboys owner Jerry Jones about the anthem issue—he reportedly called Jones four times in a day to talk about the protests. Many other owners donated to Trump’s inaugural committee. Proving his views on Kaepernick and peaceful protests of injustice contributed to Kaepernick’s absence from the league would require details about his conversations with ownership, though.

The NFL’s collective bargaining agreement defines collusion as follows:

No Club, its employees or agents shall enter into any agreement, express or implied, with the NFL or any other Club, its employees or agents to restrict or limit individual Club decision-making...

The breaking point for Kaepernick was when he was passed over by the Titans and Raiders two weeks ago, according to La Canfora. Tennessee signed Brandon Weeden and the Raiders held steady with E.J. Manuel and Connor Cook.

“Kaepernick's lawyers might argue Trump acted as an implied agent in this instance as neither team was responsive to Kaepernick's agent making clear Kaepernick's desire and eagerness to work out for any clubs,” La Canfora reports.