It doesn't make any sense that we're not starting Helenius.
I can only assume that he doesn't want us to play a traditional 442 with him and Kovak (which I somewhat agree with). Whilst people say Helenius is good dropping deep, I'm not sure he's got the mobility to become an extra midfielder when we need to bulk up the numbers.
In fact from my very limited sightings his style reminds me of Teddy Sheringham. Useful at dropping deep to find space and make passes, but certainly not an extra midfielder from a defensive perspective.