Hard to tell without knowing Rose's return. If Rose does return, how long will it be until he gets into game shape? Will he be the same? Best case senario is probably after the all-star break with him returning to form. Then you got a steal. Worse case senario is late enough in the year with the Bulls out of the playoff race(not sayin' the Bulls won't make it, just a worse case senario) and it is decided to hold off on deploying Rose until next year is better. Then you wasted a roster spot for nothing.
It's a roll of the dice. Personally, I am impatient when it comes to fantasy and avoid injured players. I would take the Derozen side all day long because I won't have an idle roster spot. But that's me. It's a high-risk/high-reward situation. Derozen, even without the benefit of his recent inflated game, edges Pekovic in value. If you are doing well and can hold a roster spot hostage for a while, take the gamble. If you want to build your record up now, pass on this.