This is just a theory (yet not as ridiculous as the infamous six-month silent ban).
I'm surprised nobody connected the dots by now. Think about it.
After some amazing results at the start of the season, and with all due respect to Del Potro, you must admit that Djokovic was off (and kinda pale) on the day of Indian Wells semifinal match that ended his big streak. His strategy there was abysmal, and it got even worse against Grandpa Haas less than two weeks later.
That semifinal loss happened on March 16th, correct?
I too would probably have breathing problems and ask for smelling salts if I were in the young millionaire's shoes that day (check the date):
Cyprus Bailout; The Start of the Next Financial Crisis
Monaco may be tax haven for many sports(wo)men from Eastern Europe (each and every successful player from my country has a condo there), however, Russians and Serbs always gravitated more to Cyprus.
Djokovic is #3 on the list of all-time tennis money machines, so imagine if he got threatened by a serious haircut on Cyprus; he'd have plenty to calculate and think about (tennis far from the first place).
Who knows, maybe he'd even start to wonder would he save more cash if he'd been honest from day one and never avoided paying tax in Serbia?