I've read that, too. I've also read that at first it will only be 30-40,000 sent to the front. I've also read that most of the troops will be sent to releave non-combat support positions near the front to allow more experienced troops to fight. Most importantly, I've been reading...since about April...that Russia is running out of missiles, tanks, and/or ammunition.
Since that last one is obviously not true, I have to question how much of the others are also not true.
Which is why I wrote it is yet to be seen what change the reinforcements will bring to the war.
So far the Russians have shown themselves to be better at fighting than PR, but maybe that last is just a testament to how good the US is at controlling the narrative outside the Russian sphere of influence.