HSV striker Ivica Olić had a serious allergic reaction to the medication received to ease back pain, and was admitted to hospital on Friday night.
After successful treatment, Olić was held for observation, and was released on Saturday.
Croatia manager Niko Kovač spoke to Olić, the player confirming he will be available for national team duty starting 3 June.
Olić's HSV still has a match to play in Bundesliga relegation play-off second leg against Karlsruhe. In the first leg, Ivo Iličević secured HSV a 1:1 draw.
