Is it hurt or something? Can you put it back in the park? If not, yes definitely seperate it and be careful yourself. Squirrels don't usually have rabies but they can harbor other diseases. Look up wildlife rehabilitators in your area and call to ask if they can take it in if you aren't a rehabilitator yourself (I'm writing with the assumption you're not, though).
I live in mass, so I have no idea what animal control does there but I called them once because I found two very young baby racoons in the middle of the road during a rain storm and they told me they don't deal with wildlife unless they had bit me then they'd take them and do brain biopsies. I was like umm...huh? Don't deal with wildlife?? Plus, it's illegal to have wildlife (at least in mass but I think it's most places). So legally, animal control might have to take it and I have no idea what they're protocol is after that.