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.
Borussia Dortmund kept up the pressure on Bayern Munich at the top of the Bundesliga on Sunday with a 2-0 win over Mainz.