Yep, sound like a two home kitty.

It is worth taking him to the vets to be scanned and see if he has a microchip and to check out the funny walk, if it is a new injury in might need treatment.

Does he have a collar tag ?

If you find out he is stray, please have him checked for aids & Leukemia before you adopt him, it will save pain & heartache on both sides later on.

Never bring a new animal straight into a house with existing pets, as even cats that look healthy can be very sick.

Put new cat in an isolated room until all tests are clear and any ownership matters resolved. Give new cat his own water/food bowls in the same room and DO NOT let your cats in that room and wash your hands well with soap & water after you touch new cat.

I'd love to hear a update. (Pref after he has been to the vets)