The 31-year-old signed a one-year deal with New England in April.
In his first NFL action in eight months, he hauled in seven receptions for 87 yards and two touchdowns against the New York Giants on Thursday.
Afterward, he said he wanted to build on that performance as he looked to "keep getting better." He also revealed he feels "a lot better" than he did before the injury, crediting the team's recovery program for helping him get stronger.
At that point, Thomas appeared to be a good bet to make the team as he had shown signs of returning to his Pro Bowl form.
Thomas is coming off his least productive season since 2011, which was before he established himself as one of football's best receivers. While splitting time between the Denver Broncos and Houston Texans, he hauled in 59 passes for 677 yards and five touchdowns.
Before that, he had recorded six straight seasons of 900-plus yards, including five 1,000-yard campaigns.
While Thomas reportedly did not make the cut, there is speculation he could be back in New England before long:
Of note, the 6'3", 225-pound wideout has missed just one game over the last seven seasons. He did not miss a contest from 2012 to 2017.