Hamburg supporters have started a petition to sign Wigan Athletic and Northern Ireland forward Will Grigg.
United States forward Bobby Wood is to join Hamburg from German second division side Union Berlin this summer.
Bayern Munich were held 1-1 at home by Borussia Moenchengladbach on Saturday as Borussia Dortmund kept the Bundesliga title race alive.
Borussia Dortmund recovered from their shock Europa League defeat to Liverpool with a 3-0 win over Hamburg in the Bundesliga.
Bayern Munich remain on course for a record-breaking fourth successive Bundesliga title with a 3-1 victory at Stuttgart.
Bayern Munich maintained their lead at the top of the Bundesliga with a hard-fought 1-0 win at home to Eintracht Frankfurt.