In July, 1942, Germany's General von Manstein won the siege of Sevastopol. Shortly thereafter, Manstein and his 11th Army were sent to Leningrad, which the Germans were also besieging.
I don't question why Hitler wanted to reinforce the siege on Leningrad. I do question why Hitler moved the 11th Army all the way from the extreme south to the extreme north for this purpose. (I can understand the transfer of Manstein "personally" to Leningrad.)
Was it a case of the 11th Army representing "picked" troops, perhaps because of their recent success with at Sevastopol? Was this Hitler's rotating "spare" army? Or was there another reason to use the 11th Army and not another one as reinforcements?