First of all, don't assume it's aspergers. Autism is a very broad-range social/mental disorder, and very difficult to diagnose even for experts. You, I assume, are not an expert on neuroscience, psychology, or sociology, so you should not assume that this person's behavior is necessarily aspergers, or even autistic.
Second, don't assume they'd want to talk about it if it is. Many people do not feel comfortable taling about a social/mental disorder, so don't treat it as something they would definitely be willing to talk about even if you can somehow confirm it is the case.
Third, unless he specifically asks for it, don't try to provide your own special accomodations. Or rather, be patient, be reasonable, explain yourself, and be courteous as you would with any other fellow employee. If you feel there is a problem with team cohesion, address that, not any perceived social/mental disorder he may have. And if it is not interfering with work in any significant way, consider whether or not this is a problem that needs addressing, or simply an idiosyncratic personality.
I have autism, and I have trouble relating to people and how they feel and express emotions. I'm 'difficult to read' and try to compensate by being a little bit outlandish in my behavior, and I'm very sensitive to high levels of noise (not 'loud', but persistent and multi-directional noise) and high levels of light. And I've learend to situate myself in ways that deal with these issues. I haven't told my boss I'm autistic, and unless I feel it is completely relevant in some way to my work, I never will and don't expect him to ask or address such a thing. And if it becomes a work problem, I will find a way to handle it.
You or your boss interviewed this person, and determined they are qualified for the job. If you feel that is not the case, that specific concern is what you need to address more than anything else.
Edit: A minor correlary, but one that should be addressed - if this person says they have Aspergers, believe them. Don't create an even more hostile environment by trying to deny it, but still treat the problem as separate from the Aspergers. A work-related problem is a work-related problem, regardless of what disability this person may have.