All 32 teams were invited to a workout organised by the league, with over 20 said to be set to attend the session. It was scheduled for 15:00 local time (20:00 GMT) at the Atlanta Falcons' training facility, which was attended by both supporters and detractors of the quarterback in anticipation of his arrival.
However, the workout has now been pushed back to 16:00 at an alternative location, after his agents hit out at the NFL.
"Because of recent decisions made by the NFL, the workout for Colin Kaepernick will be changing to an alternate location in Atlanta which will now start at 4pm," a statement from Ben Meiselas and Jeff Nalley on behalf of Kaepernick read.
"All representatives from clubs are invited to attend and will be provided the location. Further, all media will be invited to attend and upon request will be provided with the location.
"From the outset, Mr. Kaepernick requested a legitimate process and from the outset the NFL league office has not provided one.
"Most recently, the NFL has demanded that as a pre-condition to the workout, Mr. Kaepernick sign an unusual liability waiver that addresses employment-related issues and rejected the standard liability waiver from physical injury proposed by Mr. Kaepernick's representatives.
"Additionally, Mr. Kaepernick requested all media be allowed into the workout to observe and film it and for an independent film crew to be there to ensure transparency. The NFL denied this request.
"Mr. Kaepernick simply asks for a transparent and open process which is why a new location has been selected. Mr. Kaepernick looks forward to seeing the representatives from the clubs."
Kaepernick has been out of the league since the end of the 2016 season, during which the former San Francisco 49ers quarterback attracted controversy by kneeling for the United States national anthem in protest against racial injustice and police brutality.
He filed a grievance against the NFL in 2017, accusing owners of colluding to keep him out of a job. Kaepernick settled that grievance in February.
Kaepernick has long since maintained his readiness to play in the NFL again and in October his representatives released a fact sheet in an attempt to address "false narratives" and "set the record straight". The document detailed Kaepernick's many accomplishments with the 49ers, whom he led to Super Bowl XLVII, which they lost to the Baltimore Ravens.
In his career with the 49ers, which encompassed two NFC Championship game appearances as well as the narrow Super Bowl defeat, Kaepernick threw for 12,271 yards and 72 touchdowns and 30 interceptions. He ran for 2,300 yards and 13 touchdowns.
Photo Getty Images Caption: Former 49ers QB Colin Kaepernick