Loew, who had been expected to give Hummels more time to rest a thigh injury, made no other changes to his starting line-up for the world champions' opening 2-0 win over Ukraine.
Midfielder Bastian Schweinsteiger, who came on as a substitute to score Germany's second goal against Ukraine, starts on the bench again.
Poland's first-choice goalkeeper Wojciech Szczesny was ruled out by the thigh injury he sustained in his side's 1-0 victory over Northern Ireland.
His place is taken by Lukasz Fabianski but Szczesny is expected to return for his team's final group game against Ukraine.
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(Reporting by Patrick Vignal; Editing by Ian Chadband)
