Nursing a bruised heel, Allen sat out on Tuesday, but the Celtics still ended the Rockets' 22-game winning streak -- the second longest in NBA history -- with a 94-74 rout.
Celtics coach Doc Rivers told reporters on Monday that he doubted Allen would be ready to face Houston on Tuesday, saying Thursday's game in Dallas is more likely.
They may need him. Tony Allen started in Ray Allen's place on Tuesday, but he absorbed a flagrant foul late in the third quarter and crashed to the court. He left with what was characterized as a hip injury and did not return after scoring six points.
Ray Allen played only 12 minutes in the Celtics' loss to Utah on Friday and missed Saturday's win at Milwaukee.
Relying on newly acquired Sam Cassell down the stretch on Monday, the Celtics rallied to beat the Spurs 93-91. Cassell finished with 17 points in his most productive game with Boston.
Tony Allen also replaced Ray Allen, who is averaging 18.3 points and 4.0 rebounds, in the starting lineup on Monday, but point guards Cassell and Rajon Rondo saw plenty of time together. Rondo had 20 points and six rebounds.
Information from The Associated Press was used in this report.