The logistics could not be more convenient for McCullough, who lives in the Crown Heights area of Brooklyn. He can spend the whole day and night in a single borough while playing in two leagues with two sets of teammates. It has been done before, though rarely. Historically, four players — Jordan Farmar, Cleanthony Early and Coby Karl in addition to McCullough — have participated in D-League and N.B.A. games on the same day. McCullough is the first since Karl, nine years ago, to have played on both ends of a doubleheader on more than one occasion.

The situation is also ideal for the Nets’ staff, for evaluation purposes.

“We’re very fortunate to have the D-team based in our building,” said Sean Marks, the Nets’ general manager. “Our coaching staff watches them. Our front office is able to watch practices. They’re really under our noses.”

Marks added: “Chris came out of college having played half a season. I look at him as this is his first year in the league. It’s about building him up, giving him meaningful minutes. Then we’ll see where we go from there.”

Many N.B.A. teams are following this same model, partnering with D-League teams that play very near the top club’s arena. At present, there are 22 D-League teams, all affiliated with N.B.A. franchises — although players not under contract with the parent clubs are free agents who can sign anywhere. The goal is to increase the D-League to 30 teams, one for each N.B.A. franchise.

The Chicago Bulls, the Charlotte Hornets and the Los Angeles Lakers are among the teams that have D-League affiliates very close to home, within easy commuting distance. Recently, Marshall Plumlee, who was playing for the Westchester Knicks in White Plains, arrived only a bit late for a noon Knicks game when he was informed at 10 a.m. that he was needed.