Acquired in a multiplayer trade, Gay is expected to make his debut Wednesday night when the new-look Kings try to deal the Utah Jazz their fifth straight defeat.
The Kings also traded Luc Mbah a Moute to Minnesota for forward Derrick Williams on Nov. 25 in a swap of forwards.
Gay, Gray and Acy weren't available Monday, but Gay watched as Sacramento defeated Dallas 112-97. DeMarcus Cousins led the way with 32 points and 19 rebounds for the short-handed Kings, while Williams had a career-high 31 points and shot 12 of 16. Isaiah Thomas added 24 points and 12 assists in his first start.
''I guess I came on a good day because the team was playing great,'' said Gay, the centerpiece of the deal. "Obviously DeMarcus and Derrick played well. So this is a good start and I can't wait to get out there with the guys.''
Gay, averaging 19.4 points and a career-high 7.4 rebounds, adds scoring punch to a Sacramento team that ranks near the bottom of the Western Conference with 98.7 points per game.
The Kings have shown improvement recently, averaging 106.4 points in their last five contests. They shot 46.9 percent from the field and outscored the Mavericks 23-5 on fast-break points despite using only 10 players.
''We didn't care if we had 10 or 15 players, we had enough talent to win this game,'' coach Michael Malone said. ''... Our next challenge is to figure out the new guys and how they're going to play and at what position.''
While Gay is expected to join Thomas and Cousins in Malone's new starting lineup, it's uncertain who will take the other two spots between Williams, rookie Ben McLemore and Jason Thompson.
That question will be answered when the Kings go for their second victory in five days over the Jazz (4-19). Cousins had 28 points and Thomas scored 26 to help the Kings pull out a 112-102 overtime win at Utah on Saturday.
Gordon Hayward and Trey Burke combined for 41 points for the Jazz despite going 11 for 36 from the field, while Alec Burks added 19 off the bench.
NBA-worst Utah dropped its fourth straight Monday, 105-94 to visiting Portland. Burks - averaging 17.4 points over his last five games - finished with 20 while Enes Kanter had 19.
''I thought we were doing a better job out there,'' coach Tyrone Corbin said. ''I thought execution on the offensive end is getting a lot better.''
The Jazz will also look to tighten up defensively after allowing 108.7 points over their last seven games. They gave up 99.2 over the first 16.
In the teams' most recent matchup in Sacramento, Thomas scored 25 points, Marcus Thornton had 24 and Thompson added 21 for the Kings in a 120-109 victory Feb. 9.
The Kings have won five of the past seven home meetings.