Not sure to what extent your protection is like. Rain...knocks etc?
Get a hood if its purely for protection against knocks. There are some collaspsible rubber hoods as well as the usual plastic kinds.
With a filter, assuming you knock into something hard and it cracks, depending on the severity, the outer glass element of the lens may be scratched or crack. Some swear by filters as it will prevent scratches on the lens element if something does happen. Personally, I take care of my stuff and have not scratches so far on the glass.
If its to protect against rain, water etc, the filter will be more applicable. But do get a decent one. Cheap ones may cause flaring. Or just buy a cheap one and remove it before shooting.
For maximum protection, get a filter and hood. I use only a hood due to the hassle of removing the filter.