Is Costa off the Boil?

At the beginning of the season, Diego Costa was an example Jose Mourinhio's brilliant transfer window skills.  Scoring nearly every game and putting himself on top of the premier league scoring chart.  But now he has gone off the boil, one goal in four games just isn't what we had been expecting when Costa came back from his ban.

A similar thing can be said of Sergio Aguero, once challenging Costa at the top, after he has come back from his lengthy break for injury, he too hasn't been hitting the back of the net as often as he should be.

These two strickers are both key to their clubs title challenges and if they can't get back on the scoresheet every two games at least, an end of season transfer could be on the cards for both of these two star strickers.