According to the Los Angeles Daily News, when asked if he knew when Gasol would practice or if he had a target date for his return, Jackson had said: "No. We're starting to look toward Christmas, though. Some time out there."
Gasol has been frustrated by the pace of recovery from a sore hamstring. The newspaper reported that he will miss his eighth straight game on Thursday.
Jackson told ESPN that the Christmas comment was a joke and that his big man was day to day with the injury.
The defending champion Lakers are 6-1 without Gasol this season.
The Spanish forward missed just one regular-season game last year and was the Lakers' second-leading scorer while averaging 18.9 points, a team-leading 9.6 rebounds and 3.5 assists.
Jackson did tell the newspaper that Gasol's injury was rather mysterious.
"Yeah, because with most hamstrings you see bleeding or bruises or holes in the hamstring," the coach said. "His has been one of those things wasn't a big concern to us, but has turned into a month-long injury."
Information from The Associated Press was used in this report.