Devastating blow for the San Antonio Spurs -- the team is expected to be without superstar big man Victor Wembanyama for the rest of the season due to a blood clot in his shoulder.
The team announced the news just minutes ago ... saying 21-year-old Wemby was diagnosed with deep vein thombosis in his right shoulder.
The Spurs added the condition was discovered after the French baller returned from All-Star Weekend in San Francisco .