By rule, Lewis, 29, was eliminated from playing for any team in 2021 when he was placed last week on the reserve/left squad list. He was aware of that possibility and wasn't surprised when the Jets used that designation, the source said.
Lewis' head injury wasn't the reason he left the team, as the Jets suggested soon after his abrupt departure.
"He's going through some things which are much greater than football right now," coach Robert Saleh said on Aug. 7. "We're just giving him a chance to kind of sort through it all."
Lewis' retirement culminates a tumultuous year.
The former starter spent time last season on the non-football injury list as he sought medical help for an undisclosed condition. That came after a heated practice-field exchange with then-coach Adam Gase.
In the offseason, the Jets replaced Lewis by drafting guard Alijah Vera-Tucker in the first round. Lewis wasn't happy, a source said, prompting him to skip the voluntary portion of the offseason program.
The Jets approached Lewis about a pay cut, and the two sides agreed to a reworked deal in May. His base salary was lowered from $5.8 million to $3 million, and the final year of his contact (2022) was voided, which would have allowed him to become a free agent.
In theory, Lewis could try a comeback in 2022, but "it remains to be seen whether he has any desire to play again," the source said.
Lewis, a fourth-round pick of the Baltimore Ravens in 2016, played three years with them before being traded to the Jets in 2019. He did a solid job at left guard and was rewarded with a three-year, $18.6 million contract.
He played in 44 career games, with 39 starts.