Mourinho concerned over Diego Costa's conditioning

In case you haven't noticed, Diego Costa has slowed down a bit since his blistering start.  Granted, this was always going to be the case, he and everybody else knew it.  Seven goals every four games is a pace that's tough to keep up in video games on easy mode let alone in real life.  And then came (or returned, as it may be the case) all the hamstring and various minor ailments, which lead to missed games, missed training, and strained relations with the Spanish national team.

Mourinho however isn't so much concerned with the relative lack of goals -- just two in the striker's last seven games -- but rather with what's behind Costa's subpar play as of late.

"For me, the problem is not the goals - they will come as a consequence of his condition. He has to improve his condition."

"He was injured and had many doubts because he went a long time without training. Obviously that must have an effect on a player in the way he runs, the way he moves and in his co-ordination."

"I don't think there is any problem but he has to recover."

-Jose Mourinho; source: Eurosport

Ok, so the problem is his conditioning, but there is no problem?  If it's not a problem, then why even bring up conditioning?  If his conditioning is a problem, why are we playing him three times a week whenever we possibly can?  Or is that the only way to improve his conditioning?  Is Mourinho strictly referring to match fitness or is Costa still carrying some nagging injury?

Either way, I'm concerned that Mourinho's concerned (but not really; ok, maybe).  Let's figure this out before the festive period, please.