This is correct, as there were ethnic Poles in Wehrmacht. Their presence is related to the Deutsche Volksliste (DVL) or German National List. This was the action introduced by Heinrich Himmler on 2nd September 1940 in Germany and conducted by Stabshauptamt Reichkomissar für die Festigung deutschen Volkstums (Main Office of the Reich Commissar for the Strenghtening of German Nationality), responsible for promoting German culture and overseeing population re-settlement. The List has been introduced on the Polish territories annexed by Germany (Eastern Prussia, Danzig and Pomerelia, Wartheland and Upper Silesia) on 4th March 1941. Three latter territories were annexed rather than occupied as they were considered to be 'reclaimed German territory' with a substantial German minority, while the Eastern Prussia was a territory that evolved from a land of the Teutonic Order that became a Polish fief and later a part of Prussia that also annexed part of nearby Polish territory in the First Partition of Poland in 1772 and thus was a home to a large Polish minority.

All citizens of the annexed territories were asked to fill a special form that contained various personal data, including known language, education, religion, how long the family of the respondent lived in the given area, the nationality of parents and grandparents and so on. Then, the officials at the Kommissar's Office could have grant the German nationality to a given person without further input. There were four possible categories, with the first two encompassing German nationals (the distinction was based on whether they were actively pursuing the German interests in the interwar period, or not), and the fourth category was formed of ethnic Germans who accepted Polish nationality and cooperated with the Polish authorities to large extent, or ethnic Poles who identified as Germans and were deemed to be 'of Germanic descent'. Majority of the Poles registered as Germans belonged thus to the third category (ger. Eingedeutsche) or people considered by at least partially Germanized, living for a long time within the territory belonging to Germans or people married to ethnic Germans (all these people were granted German citizenship valid for 10 years). People who declined filling the form were threatened with the relocation to a concentration camp. In the Upper Silesia, the rules were exceptionally harsh, as on 16th February 1942, all inhabitants of that region who did not identify as Germans (usually declaring Polish nationality, or, rarely, Czech or Slovak one) were obliged to re-apply for the German citizenship under the penalty of imprisonment and, since mid-1944, under penalty of death, at least officially.

From the moment of being added to the DVL and being granted German citizenship, inhabitants of the annexed lands were considered Germans and subject to German law. This, of course, meant that they were also subject to mass conscription, and thus it is largely accepted that the introduction of the aforementioned activity in March 1941 was a part of preparation for the invasion of USSR. As the annexed regions were relatively densely populated, this could have increased the population of Germany by several millions (until 1942 roughly 3.1. million people in these territories were granted German citizenship). It should be noted however, that some of the 'Eingedeutsche' could have been sent into the German heartland to work, although, unlike many Poles sent to perform labour (it was the work at regular farms or factories, to replace conscripted workers, not at labour camps that were a completely different story) but they retained some degree of freedom and had more opportunity to escape in comparison with their compatriots who were made to join Wehrmacht or Poles without German citizenship sent to forced labour.

As one could predict, ethnic Poles granted German citizenship and conscripted were generally not trusted and thus they were punished more harshly for any transgressions, their opportunities were strictly limited (they usually could not have advanced beyond the rank Oberschütze [Private First Class] or its equivalent in other units) and they were dispersed throughout units so that there were no more than 2-3 of them in a single company to minimize the chances of coordinated desertion or surrender.

Overall, the total number of ethnic Poles in the Wehrmacht amounts to roughly 375.000, out of which 225.000 were citizens of Poland before 1939 (the remaining ones were members of Polish minority in Germany). Out this number over 316.000 were killed, lost or captured during the war. Now, the number of 90.000 is sometimes misconstrued as the number of deserters from Wehrmacht, while in reality this is the total number of ethnic Poles who were conscripted by Germans and then joined the Polish Armed Forces in the West (PAFW). Although some of them were actual deserters (especially in the early and late stages of war), the majority of them were German prisoners of war who, after explaining the realities of their conscription were often released and allowed to join PAFW.