Schroder left the bubble to be with his wife for the birth of their second child on Aug. 3. He returned to Orlando, Florida, on Aug. 10 and cleared quarantine on Friday morning.
The Sixth Man of the Year candidate scored 17 points in 25 minutes during a 107-103 loss to the LA Clippers.
"The NBA did a great job, OKC did a great job bringing me to my wife to support her," Schroder said. "Came back and had to quarantine for four days. It was pretty rough, staying in a small room was pretty tough. I'm back now. Left my room today and got a little [practice] session in at 11 [a.m.] and was able to come back tonight."
With his sixth man back, Thunder coach Billy Donovan said he will use the next several days to work on his point guard-heavy lineups with Chris Paul, Shai Gilgeous-Alexander and now Schroder back in the mix. Oklahoma City faces Houston in its first-round series starting Tuesday.
"I think we need to have some time with some different lineups now that Dennis is back," Donovan said. "... Now we are back into a situation where we can play two of those three guys [together], if not all three of them. And we probably got to get some time in practice where they are all working and playing together. We really haven't had a lot of that."