Player decreased Role familiarity help

[Mike1987]

Ill get straight to the issue, basically at the end of my 1st season in charge of United i sold Mata to Real Madrid and hence needed a AMC replacement, at that time i couldnt get any of my desired targets for various reasons so i plumped for Paulo Dybala even though he wasnt a natural in either the AMC position and nothing more than 'competent' in any of the AMC roles his stats were perfect for the position and i always planned on using him as a striker in the long term anyway, he was just intended to be a stop gap for a season until i could get a specialized AMC which i now have in James Rodriguez.

Anyway here comes the problem, after a season of playing and training him as an AMC/Attacking Midfielder he has now become 'Natural' in both the position and the role of attacking midfielder, thats not the problem in fact im delighted ive now got an excellent player perfectly capable of playing in a position he wasnt natural in before...BUT for some reason when i now go to put him back up front whilst hes still rated as a natural in the centre forward position hes nothing more than 'competent' in any of the striker roles and this is what i fail to understand and could use some help with. I dont see why merely 1 season of playing in a slightly deeper position should cause him to lose the ability to play as a complete forward or any type of forward for that matter? Is it just a case of me playing and training him back in that role and he'll become natural in it like before or have i now permanently changed him to an attacking midfielder?? i hope not because that was never the intention and as mentioned above now i have Rodriguez (as well as Lincoln and a superbly developing Callum Gribbin for this position) i no longer need Dybala there but hes struggling as a striker now and i cant help but think thats purely because hes not overly comfortable in the role.

Anyone else had experience with this and can shed some light on what to do? any feedback would be appreciated.