Little background on the shirt for anyone thinking this was something Kovalev had made or used his kid to advertise. The shirt itself is made for kids by a company named Japan Rags. At the bottom of the shirt it says welcome to new york.
Japan Rags Bays White "Boxing Monkey" Short Sleeve T-shirt

It appears his only child is the one that was born just last year in October and just over 6 months old. The body for the shirt appears to an old rocky poster (by the design of the belt and the velcro on the parring gloves) maybe which would make the monkey white. That's probably something the kid chose to wear when he was going to meet kovalev or to an event where he would meet boxers..