Simon Terodde was previously HSV's life insurance company in the battle for promotion.
The striker, who leads the top scorer list in the second division with 20 goals, has often made the difference with the Hamburg team this season.
Coach Daniel Thioune will have to do without the 33-year-old in the next two weeks - Terodde was diagnosed with Corona.
"I feel a bit weak, but otherwise have no typical symptoms and I'm happy that the other guys are all healthy," Terodde was quoted in a club statement.
He is now in quarantine for 14 days.
His teammates were allowed to resume training on Tuesday after approval by the responsible health department.
The game on Saturday (1 p.m. / Sky and in the WELT live ticker) against 1. FC Heidenheim is currently not at risk.
On Monday, Hamburger SV initially spoke of a suspected corona case, but did not name Terodde.
The afternoon training session on Monday had been canceled as a precaution.
Holstein Kiel and Hannover 96 in quarantine
The league competitors Holstein Kiel, Hannover 96 and Jahn Regensburg recently reported corona cases and several games had to be postponed.
The entire team and parts of the functional team from Kiel and the players from Hannover 96 are currently in quarantine.
Jahn Regensburg has just ended the quarantine and is playing his first of two catch-up games against SpVgg Greuther Fürth on Wednesday (6.30 p.m.).
Due to the incidents in Hanover and Kiel, HSV introduced a drive-in procedure in the bus entrance on Monday and subjected all players and team members to individual rapid tests before the regular PCR tests were due in the afternoon.
Therefore, the team hadn't met before the tests.
So the Hanseatic people were able to prevent the entire team from having to be quarantined.
After the laboratory tests had confirmed the suspected case at Terodde, all professionals and team members were tested again.
With the result that regular training was possible again on Tuesday afternoon.