Malkin was injured in the third period of Friday's game against the Panthers after getting nudged by Florida's Erik Gudbranson. Malkin's back hit the boards at full speed and his head snapped back upon impact.
Pittsburgh announced the diagnosis Sunday night and said that Malkin had suffered some short-term memory lapses.
"After the hit Evgeni suffered some short-term memory loss and therefore was diagnosed with a concussion," coach Dan Bylsma said on the team's website. "He's had no other symptoms. He's feeling fine and his memory is returning."
The Pittsburgh Tribune-Review reported Malkin had symptoms that included a severe headache and mild disorientation, but Bylsma disputed the report.
Bylsma said the club was following "NHL protocols" and will monitor how Malkin recovers before giving any sort of timetable on when he might return.
Pittsburgh's second-leading scorer, Malkin has registered 14 goals and 25 points in 22 games this season. The Russian center collected 50 goals and 109 points last season en route to winning the Hart Trophy.
Information from The Associated Press was used in this report.