Beckham has skipped the Giants' offseason training activities over the past month, with his absence perhaps linked to his desire for a new contract. The workouts are voluntary so he can't be disciplined.
Star defensive end Olivier Vernon, who was also absent for OTAs, is also in the building, NFL.com reported, citing a source. The reason for the absence is not immediately known for Vernon, who is notoriously private about his off-field activities.
The 24-year-old Beckham posted an Instagram video early Monday, including the words "The rain falls on the just and unjust alike... #ImBack"
Beckham is slated to make $1.8 million this season under his rookie contract. The team picked up the star wideout's fifth-year option for 2018 at what is likely around $8 million.
Beckham added a Nike endorsement deal over the past week, with the contract reportedly paying Beckham more than $5 million annually over the next five years.
Beckham attended parts of the Giants' offseason workouts earlier this year. But he has spent ample time away from the team working out in Southern California with a group of players that include quarterback Johnny Manziel and running back Reggie Bush.
The three-time Pro Bowler caught 101 passes for 1,367 yards and 10 touchdowns last season. He also was fined six times for various disciplinary things and his off-field life also has come under scrutiny.
Beckham has caught 288 passes for 4,122 yards and 35 touchdowns in three NFL seasons.