Since you' seem new I'm gonna tell you the hard truth. I suggest you finish your One on one special ability since you are halfway there, but it won't make much difference I have tried giving SA to many players with little to no effect. Only players with existing special abilities seem to make a difference (the ones you buy from market , scouts, negotiations etc)
Like Toxcatl said the ST not scoring enough problem is very common. You shouldn't worry as long as he gets good grades above 7 and your team is winning. A bad player can't be transformed into a good player, it is best to change him. Next time don't waste packs on players that you think are bad instead buy a new one and invest those on him or on your currently good ones.