I really hope Leo can have a bit of extra time to recover from all this.
He has been carrying Argentina & Barca hopes as the man who should win games single handed for 3 or 4 years now, that's immense pressure and what with his injuries and being rushed back in 2013, maybe its all gotten to him.
I think we can rule out Laziness. Its clear to watch him that something is wrong, but he is not so static through choice.
IMO as some have suggested maybe its the huge pressure and injuries that have drained him emotionally, mentally and physically.
I think its something that can be worked on, but Barca have got to take it seriously and not just make him play every match and focus everything on him, even if Leo is unhappy with that. Let him have some time off and relax, then start a fitness regime similar to the Pep days when Leo stayed injury free and couple that with more regularly subbing him off or on in order to give extra rest that way. He also needs to be worked with mentally in case Leo is struggling through fear of injury.
All in all the system needs tweaking at Barca, to ease pressure on Messi by not playing "look for Messi everytime" and use Neymar & Suarez to get the most out of them too. Which must include the new coach telling Leo to miss some games and also telling Messi when he is playing bad and not be too scared to say anything.
I hope Leo can come back fresher than expected by getting extra time to rest and relax.
Otherwise this "burnout" will only get worse.
Of course Leo needs to let this happen and not insist on playing every game.
If that doesn't work then things get more serious.