Putin's plan to replace combat losses

 ISW:

Russian President Vladimir Putin’s August 25 decree to increase the size of the Russian military starting in January 2023 is unlikely to generate significant combat power in the near future and indicates that Putin is unlikely to order a mass mobilization soon. The decree increases the nominal end strength of the Russian Armed Forces by 137,000 military personnel, from 1,013,628 to 1,150,628, starting on January 1, 2023.[1] The Russian military likely seeks to recover losses from its invasion of Ukraine and generate forces to sustain its operation in Ukraine. The announcement of a relatively modest (yet likely still unattainable) increased end strength target strongly suggests that Putin remains determined to avoid full mobilization. The Kremlin is unlikely to generate sufficient forces to reach an end strength of over 1,150,000 soldiers as the decree stipulates. The Russian military has not historically met its end-strength targets. It had only about 850,000 active-duty military personnel in 2022 before Russia’s full-scale invasion of Ukraine, for example, well shy of its nominal end strength target of over one million.[2]

Russia would likely face serious obstacles to adding large numbers of new soldiers quickly. Apart from the challenges Russian recruiters face, Russia’s net training capacity has likely decreased since February 24, since the Kremlin deployed training elements to participate in combat in Ukraine and these training elements reportedly took causalities.[3] Russia may use the fall conscription cycle in October 2022, which should bring in about 130,000 men, to replenish Russian losses, which reportedly number in the tens of thousands killed and seriously wounded. The Kremlin may alternatively use the additional end strength to formally subsume into the Russian military the forces of the Donetsk and Luhansk People’s Republics and/or the new Russian volunteer units that are not formally part of the Russian military. The net addition to Russia’s combat power in any such case would be very small.
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Many of the military-aged population have been leaving Russia.  Most of them are educated and have tech abilities that make it easy for them to find work in the West.  Russia has been struggling to replace combat losses for months.  When you're recruiting in the prison population it probably means that you can't find willing recruits elsewhere.

See, also:

As Russia Seeks More Troops, Both Sides Dig In for War of Attrition

There has been little movement on the front line in recent weeks, even as the leaders of Ukraine and Russia face pressure to show battlefield results.

And:

 Putin signs decree to increase size of Russian armed forces