Gay was getting therapy Saturday, and Casey said any decision could be based on how he responds to that.
"I would say that it's something that will be talked about sooner rather than later," Casey said.
Without Gay in the lineup, the Raptors lost 110-84 to the Knicks at Madison Square Garden on Saturday, their fourth straight defeat.
Gay has averaged 20 points, six rebounds and three assists since being traded to Toronto from the Memphis Grizzlies in January, however he has struggled with his shooting from both the floor (40.2 percent) and the free-throw line (74 percent).
Information from The Associated Press was used in this report.