Surely Roger won´t be playing Monte Carlo, why ? Because after Australian Open he has had deep runs in Rotterdam, Dubai, now Indian Wells (with that sickness) and still Miami is behind doors. Playing Monte Carlo is only a wishful thinking of some fans, who doesn´t bother by players fatigue, or regeneration, just points, points, points.
Novak will be playing Monte Carlo, as his residence is over there and he will be playing another Masters 1000 (he has one zero-pointer, cause he didn´t play Shanghai and Monte Carlo last year). That is the reason, why he don´t have to play Belgrade, as it is only 250 tournie.
Think about it.