BoxRec

I just watched about 6 of Kovalev's early fights, felt like I was watching the early career of John "beast " Mugabi.
I was wondering in around the 6th fight I saw Don Turner in his corner, then fights 16, 11, 14 I see able Sanchez, and since I have been watching Kovalev on HBO it is John David Jackson as his trainer and Don Turner as a kind of chief second does anyone know the history of how these different people came to train Kovalev?

Most of boxers from post-Soviet states were starting in U.S. through Turner. Turner's camp is extremely strict. Kovalev called it "prison", so no wonder he spent only one year with Turner. Here is Kovalev's interview in Russian:

http://www.sports.ru/tribuna/blogs/muyzhnek/540516.html

May be OK in translated form.

I can't find anything on why Kovalev left Sanchez. The only trace is Kovalev's phrase that every sparring with Golovkin was a war, they are both stubborn and didn't want to give in. Possibly, Sanchez was favoring GGG, so Kovalev found another coach.