For as long as the verb procrastinate has been in English, it has been used both transitively and intransitively,1 meaning the word works two ways: (1) not acting directly upon anything (e.g., I had a lot of homework, but I procrastinated all night), and (2) acting directly upon something (I procrastinated my homework all night).
Still, many writers seem uncomfortable using procrastinate transitively, often inserting unnecessary prepositions (usually on or about) to keep procrastinate intransitive. In these examples, the unnecessary words are underlined:
And now something for listeners who may have procrastinated on their holiday baking. [NPR]
Procrastinating with paperwork causes much stress, so my goal is to get moving on it as soon as I return this week. [Advance]
If you’ve procrastinated about improving your public speaking skills, plan to attend this meeting. [Orange County Breeze]
Of course, using that extra word isn’t an error, and there’s nothing wrong with those sentences.
1. http://www.oed.com/view/Entry/151861 (OED entry with historical examples of procrastinate used both ways) (subscription required) ^