Kaman, whose great-grandparents were German, averaged 15.7 points and 12.7 rebounds last season with the Clippers.
The 7-foot Kaman will add size to a German team seeking to qualify for its first Olympics since the 1992 Barcelona Games.
"We'll be stronger under the baskets with Chris," Nowitzki said Thursday.
The German team is practicing at home for a warmup tournament before it travels to Greece for the July 14-20 qualifying event in Athens.
"Chris is a significant addition and we'll now have to integrate him in time for the Athens tournament," coach Dirk Bauermann said.