The Spartans confirmed Ward's possible return date is unclear but that he'll undergo an evaluation on a weekly basis.
Ward played 19 minutes in Sunday's victory, scoring nine points and collecting six rebounds. The junior is now averaging 15.1 points and 6.7 rebounds while shooting 60.4 percent from the floor.
Michigan State already lost Joshua Langford to a season-ending foot injury in January. Now, the Spartans are facing an extended stretch without their second-leading scorer and third-leading rebounder. The team stopped short of saying Ward is out for the year, but his lack of a firm recovery timetable is concerning.
The Spartans still have two games against the Michigan Wolverines ahead and a tricky matchup with the Indiana Hoosiers, who pushed them to overtime on Feb. 2.
In his most recent edition of Bracketology, ESPN.com's Joe Lunardi projected Michigan State to be a No. 2 seed, and beating Ohio State will help the team's NCAA tournament resume. A short-handed Spartans squad will struggle to win out in the regular season, so slipping into a lower seed is on the table.
And that's to say nothing of what Ward's absence would mean in the Big Dance if his injury lingers into March.