something on paw pad :(

Leo has something on his front left paw toe pad.
Its a little rough and there's a little black round scab. so it looks like. He doesn't mind me touching it. It doesn't seem to hurt him. He walks and it doesn't fase him one bit. I just noticed it. Im not sure how long he's had it either.. could it just be a callas (sp) or something?
I'm keeping my eye on it and if it progresses or starts bleeding , i will take him in. but so far, he's acting like normal kitty.
He never goes outside so maybe it's just something he got off the carpet? I don't know..

Without seeing it, it sounds like a possible scab, or a mole. If it's not painful, keep an eye on it. Check to see if it's getting bigger or changing in color. If it is, i would make an appt with the vet to have a look.