This initiative to use Posco as a DM in this game from Walmsey garners my respect, for me it's an extremely exciting 'possibillity'. If Poz can adapt to the role, he could be a revelation that could help with success this coming season.
Last season Posco performed really well in the CB role, when replacing Ando and Bos, when poor form got them both dropped at various times.
He also did really well in the RB role & imo out performed Storm Roux who was dropped often from the squad.
At RB he goes forward really well. Linking up with AM's using 1-2 passes effectively and putting in good crosses for the front men.
Considering his understanding of 'all of the above' coupled with that aggressive defending quality and his speed I think he could make an excellent DM alongside Monty in a 4-2-3-1, with Monty being the one who sits & holds whilst we attack with Posco pushing up to support the attack- and if that attack breaks down his defensive mindset/abilities kick-in and help stifle the oppositions quick counter attacks whilst knowing Monty is in behind him covering.
I know Walmsley has been tinkering with the 4-3-3 as our new playing formation, but I see multiple possibilities of formations could be used this season with the players we now have, which again I find exciting.
Dare I say even a back 3-4-3 perhaps & really attack teams.