OXNARD, Calif. -- Dallas Cowboys star CeeDee Lamb, who has been unable to land the type of contract extension that other wide receivers have, is not expected to report to training camp Wednesday with the rest of his team, sources told ESPN's Adam Schefter on Tuesday night.

Lamb is entering the last year of a deal scheduled to pay him $17.99 million this season, and the Cowboys have been bracing for the All-Pro to miss the start of camp.

The holdout will not become official until Wednesday, but Lamb was not on the team's charter flight from Dallas on Tuesday. That is not a required flight, however, and a number of players, including quarterback Dak Prescott, were already on campus at the River Ridge Residence Inn before the buses arrived in mid-afternoon.

The Cowboys' first practice is scheduled for Thursday.

Lamb skipped the mandatory minicamp in June, leading to fines totaling roughly $100,000, although those can be rescinded by the team. He faces a daily fine of $50,000 that cannot be rescinded for every day missed in training camp, according to the collective bargaining agreement.

"I mean he's a huge part of everything we do, for sure, and his presence obviously will be missed but while he's handling things he has to handle, we have to handle business as well," Pro Bowl left guard Tyler Smith said. "And I feel like that's the best thing we can do as teammates is just make sure we're upholding the standard in his absence so when he comes back we're a well-oiled machine and we're operating at 110%."

Minnesota Vikings wide receiver Justin Jefferson re-set the market with a four-year, $140 million deal that included $110 million guaranteed. The $35 million a year average made Jefferson the league's highest-paid non-quarterback.

The Cowboys and Lamb's agent have been in discussions in recent weeks, but have yet to close the gaps on a deal that would make Lamb the highest paid receiver in team history and challenging Jefferson's deal.

Last year, Zack Martin held out of training camp for three weeks, accruing fines of roughly $1 million, before getting a re-worked deal that guaranteed him $36 million in 2023 and '24, up from the $27.5 million he was set to earn.

Lamb is coming off the best season of his career, setting a team record and leading the league with 135 receptions for 1,745 yards, which was second-best in the NFL. He also scored 14 touchdowns (12 receiving) in earning first-team All-Pro honors.