Jordan Walsh, a rookie for the Celtics, might make his NBA regular season debut against the Hawks on Sunday night.

Walsh was recalled from Boston’s G League affiliate, the Maine Celtics, just after it was reported that Jrue Holiday is questionable for Sunday and Kristaps Porzingis has already been ruled out.

Walsh is a 6-foot-6 guard who gained attention during the NBA preseason and summer league. He made the Celtics’ opening-night roster, but was demoted to Maine on Oct. 31 after failing to make the lineup in the first three games of the season.

Walsh’s relocation to Maine was expected to help his growth, but there may now be an opportunity for him to play in the major leagues.

If Holiday does not play against Atlanta, the Celtics’ lineup will be weak. Four starters will almost definitely be Derrick White, Jayson Tatum, Jaylen Brown, and Al Horford. Unless Joe Mazzulla goes with the less likely option of a double-big lineup with Luke Kornet, the fifth spot will likely go to Payton Pritchard or Sam Hauser.

Whatever the case, Boston will only have seven players of its core rotation if Holiday is unable to go, and eight if he is able to. Boston’s depth becomes murky behind them.

Aside from Walsh, the following players are in Boston’s lineup: Dalano Banton, Svi Mykhailiuk, Lamar Stevens, Oshae Brissett, and Neemias Queta. None of those five have appeared in more than eight games and none have scored more than 2.5 points per game.

Even if it’s a small sample size, Sunday could be an opportunity to see what Walsh can do in the NBA. The long guard is off to a fast start in the G League. Walsh has averaged 15.0 points, 6.2 rebounds, 2.3 assists, and 1.7 steals in six games. Early in his professional career, he has shown a lot of promise.

Walsh’s playing time will most likely be determined by if Holiday is healthy enough to play. If he isn’t, Walsh may have to fill in as the fourth guard for a depleted Boston club.