Kansas City Chiefs star running back Jamaal Charles has failed to report for practice with the team.
Despite participating in off-season workouts, Charles had threatened to hold out from training camp if he was not offered a new contract.
The Chiefs set a deadline of 4pm for Charles to arrive at their Missouri Western State University camp, but he was a no-show as the team began to train and they do not know when he intends to return.
Charles has two years remaining on a contract which he signed in 2010 and he is scheduled to make $3.9m (£2.3m) this season.
More than a dozen of the league's top rushers are scheduled to make more than Charles over the next year, with Minnesota Vikings star Adrian Peterson leading the way with a salary of $12m (£7m).
Charles has claimed that his excellent 2013 season warrants a new deal with the Chiefs. The 27-year-old led the team's rushing and receiving figures, also leading the NFL with 19 total touchdowns.
