Ilkay Gündogan even wrote "For my honoured President, with great respect.".
DFB president Reinhard Grindel said: "Football and the DFB defend values which are not sufficiently respected by Mr Erdogan."
"That's why it's not good that our international players let themselves be manipulated for his electoral campaign. In doing that, our players have certainly not helped the DFB's work on integration." said Reinhard Grindel.
Erdogan is not very popular by German politicians after the military coup in 2016. Already 50,000 people are arrested for this coup.
Both players are currently preparing for the upcoming world championship in Russia. Gündogan gave his reply in the following words: Must we be impolite to the president of our homeland? We did not want to make a political statement with this picture. It was only to pay respect to the president. A Member of parliament of Germany also said about the "My president" message: The federal president of a German international footballer is called Frank-Walter Steinmeier, the chancellor is Angela Merkel and the Parliament is called the German Bundestag.
The Turkish election will be held on June 24.