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 thrombosis in his right shoulder.

The Spurs added the condition was discovered after the French baller returned from All-Star Weekend in San Francisco ... after scoring six and 11 points in Team Chuck's two games in the four-team tournament.

While the 7'3" center will likely miss the remainder of the 2024-25 campaign due to the issue, the team said it will provide more updates as they come in.

Wemby was averaging 24.3 points, 11 rebounds and 3.7 assists for the new-look Spurs ... who recently made a big move by trading for star guard De'Aaron Fox.

The No. 1 overall pick in the 2023 draft was initially listed as doubtful for the Spurs' Thursday night matchup against the Phoenix Suns due to an "illness."

San Antonio will now look to improve on its 23-29 record without its biggest piece -- literally and figuratively.