The Broncos waited until he arrived at Gillette Stadium on Sunday night to make a decision on Thomas, who suffered a right knee injury in last week's win over the Kansas City Chiefs.
Thomas had participated in Friday's practice on a limited basis, and the Broncos needed to see some improvement for him to have played against New England. Thomas did improve some, but once the Broncos arrived at the stadium, they made the decision to make him a game-day inactive.
Thomas is fourth on the team in receptions with 45, but leads the team in touchdowns with 10.
Steve Gregory, the Patriots' starting safety and primary communicator, will miss his second straight game. He had returned to practice this week but it wasn't enough for him to clear the hurdle of being active.
Linebacker Brandon Spikes -- who was downgraded to questionable earlier Sunday (knee) -- is active for New England.
Information from ESPN Patriots reporter Mike Reiss was used in this report.