Star wide receiver Justin Jefferson, who has been in talks with the Minnesota Vikings regarding a contract extension, was not spotted at the team's training facility Monday for the start of OTAs, team sources told ESPN's Adam Schefter.

Jefferson also didn't participate in the earlier portion of the Vikings' offseason program, which like OTAs, are voluntary.

Last month, during the NFL draft, general manager Kwesi Adofo-Mensah said the team and Jefferson were making progress on a deal, although the sides paused talks during the draft.

The Vikings and Jefferson have been discussing terms of the deal for more than a year. Adofo-Mensah said previously that they got "unbelievably close" to a deal last summer before tabling the talks at the start of the 2023 regular season.

Jefferson also missed all of the Vikings' 2023 voluntary workouts before reporting for mandatory minicamp as he worked through negotiations.

Last month, Philadelphia Eagles receiver A.J. Brown agreed to a three-year, $96 million extension that included $84 million guaranteed, his agent told Schefter. Both the $32 million average annual value of the extension and the $84 million guaranteed represented new highs for a wide receiver contract.

Last season, Jefferson was leading the NFL in receiving yards (543) when he suffered a right hamstring injury in Week 5. After returning for good in Week 15, he amassed an NFL-high 476 receiving yards, the second-highest total in the league over that period. All told, he caught 68 passes for 1,074 yards in parts of 10 games, joining Jim Benton (1945) and Wes Chandler (1982) as the only players to hit that milestone in a season of 10 games or fewer.

Jefferson, the 2023 Offensive Player of the Year when he led the NFL with 128 receptions and 1,809 yards receiving, has surpassed 1,000 yards receiving in each of his four seasons. His average of 98.3 yards per game is the highest in NFL history -- for any career span.

He is set to play this season on the fifth-year option in his rookie contract, worth $19.743 million, fully guaranteed.

Information from ESPN's Kevin Seifert was used in this report.