The 25-year-old's absence stems from the lack of a long-term contract extension.
NFL Network Insider Ian Rapoport added that sides have been negotiating over the last few weeks, hoping to find common ground, but have yet to close the deal.
Jeffery Simmons recently inked a four-year extension with the Tennessee Titans worth $94 million in new money with $66 million in guarantees. It's a deal that Williams' camp would likely seek to leapfrog.
Coming off an All-Pro campaign in which he set a career high with 12 sacks and was a clear difference maker along Robert Saleh's line, Williams is set to earn $9.6 million on the fifth-year option of his rookie contract.
Given the voluntary nature of this stage of workouts, it's not a huge deal Williams won't attend. But it's a symbolic absence that underscores his importance to Gang Green's ultimate success in 2023 and highlights his desire for a new deal.