The Knicks lost, 96-93.
Billups said Tuesday night that he would undergo a precautionary MRI on Wednesday in New York.
The Knicks had previously chosen not to perform an MRI on Billups' strained left knee, which buckled when he landed awkwardly on it in the fourth quarter of Sunday night's Game 1 loss.
"It's a hole to fill, but I have a lot of confidence in Toney [Douglas], and Anthony Carter will back him up, and we'll just see how it runs," D'Antoni said after the Knicks' morning shootaround. "He [Billups] says he feels a lot better today than he did yesterday."
Douglas had 14 points in 34 minutes.
D'Antoni was in an upbeat mood for a coach whose team lost a chance to knock the Celtics on their heels, but he got a little defensive when asked if the Knicks would try to get the ball to Amare Stoudemire late in the fourth quarter more than they did in Game 1.
Stoudemire scored 12 of his 28 points in the fourth quarter but did not score over the final 2:46.
"I love people that maybe didn't watch the game, because I went back when I heard that, and at the 2½-minute mark he scored a basket, and we went to him almost every time up to that point. On the next play we came down we went to him, and that was at the 2 minute mark, and he charged. Then at 1:40, we ran a play for him. They kind of knocked him off of it and overplayed him, and that's when Chauncey got hurt -- and he had an open lane to the basket," D'Antoni said. "You know, our guys can't be robots. They've got to play. But every play that was called was for Amare."
Chris Sheridan covers the NBA for ESPN.com.