FOXBORO — The Patriots filled their 90-man roster prior to Thursday night’s preseason opener against the Houston Texans, but only 81 players were present during pregame warmups.

Safety Cody Davis, defensive end Trey Flowers and guard Mike Onwenu remain on the physically unable to perform list, and offensive tackle Calvin Anderson is still on the non-football illness list, so they were not in uniform. Several players who have been absent from practice also weren’t dressed Thursday, including running back Ty Montgomery, cornerback Jonathan Jones and guards Bill Murray and Cole Strange.

The only surprise absence was linebacker Ronnie Perkins. Perkins has been present for practice but was not spotted before the game for undisclosed reasons.

It would be a surprise if many of the Patriots’ regular starters played Thursday night, but most players are in uniform. Linebacker Joe Giles-Harris was signed Wednesday but was present in uniform No. 53.