As multiword modifiers, participial phrases enjoy flexibility in positioning themselves in a sentence. However, they do their job best when placed as near as possible to the noun or pronoun they are meant to modify: 'Tired after a long day's work, the mechanic fell asleep in the bus.' They work equally well as interrupters in a sentence: 'The mechanic, tired after a long day's work, fell asleep in the bus.' Either way, the sentence functions without a hitch because 'tired after a long day's work' is positioned right beside the noun 'mechanic.'

Take note though that when placed at end-sentence, that same participial phrase won't work properly: 'The mechanic fell asleep in the bus, tired after a long day's work.' This time, that participial phrase becomes a dangler, absurdly modifying the noun 'bus.'