The Ukrainian world number 19 is enjoying a good 2014, but his record at the clay-court tournament in Germany has been poor.
Dolgopolov continues returning to the ATP 500 event despite losing in the first round in three consecutive years.
He reached the final in Rio de Janeiro earlier this year but has been largely unimpressive on clay, including only making the second round at the French Open.
Italian Fabio Fognini returns to defend his title after a run deep on the clay in Stuttgart.
Top seed Fognini has been a standout on clay in 2014, including winning the title in Vina del Mar, Chile, in February.
Below him in the seedings is Russian Mikhail Youzhny, who has also taken a liking to the courts in Stuttgart.
Spanish veteran Tommy Robredo made a shock second-round exit in Bastad, where he lost to Renzo Olivo.
Robredo claimed the Hamburg title in 2006 and will be looking to bounce back from his loss in Sweden.
Philipp Kohlschreiber is the best of the German hopefuls in front of their home fans, but he only made the second round at the MercedesCup.
Among the other seeds are Spaniards Fernando Verdasco and Roberto Bautista Agut.
Verdasco and Bautista Agut have both had strong tournaments in Sweden and Germany respectively heading into Hamburg.
Poland's Jerzy Janowicz was also due to play, but a foot injury may see him miss out.