 The importance of the delay is still debated . William Shirer argued that Hitler 's Balkans Campaign had delayed the commencement of Barbarossa by several weeks and thereby jeopardized it . He cited the deputy chief of the German General Staff in 1941 Friedrich Paulus , who claimed the campaign resulted in a delay of " about five weeks . " This figure is corroborated by both the German Naval War Diary and Gerd von Rundstedt . Antony Beevor names a variety of factors that delayed Barbarossa , including the delay in distributing motor transport , problems with fuel distribution , and the difficulty in establishing forward airfields for the Luftwaffe . 
