You did not say what type of component you found this part of the circuit in, so I will have to guess. It looks like this portion of the circuit is some sort of DC bias injector, which provides DC voltage to an active component. In that case, the series 0 ohm resistor would serve one of two purposes:
1) a crude attenuator, where you can leave the value at 0 ohms if you want the maximum power out, and can put in 10 or 20 ohms if you want to drop the output power a dB or two.
2) a stability enhancing resistor for an amplifier output. If the amplifier oscillates with a certain load, adding a 20 or 30 ohm resistor in series with the output might cause the oscillations to cease. Note also a second resistor labelled "NP" (not populated). That 2nd resistor can add some resistance to ground to stabilize an oscillating amplifier (note that the capacitors to ground are an ac short circuit, especially if you replace the 2pF with something larger like 20 pF).