Hi.
I have a five year old Maltese. Last week I noticed him limping a little on his back left leg,(he has been playing with my aunts bigger Whippets for a week) I felt the leg and there wasn't any sign of pain, whimpering etc. when I press or massaged it. I wanted to wait a week before I took him to the vet but he is still limping. He actually rolled down the two bottom steps coming down the steps yesterday and is semi limping more and favoring his other legs, yet he is still running around, playing and walking down stairs. I haven't limited his activity yet because he is still so lively and doesn't seem in pain.

Should I take him to the vet? Limit his activity?

Thanks in advance.

I would limit his activity for a few days... he can still run around the house but no walks or any hard activity.
If there is no obvious pain then there shouldn't be anything major wrong, just a pulled muscle or the like.

Wait a week like you said and if he is still limping take him in for a check up. :)

Definitely limit his activity. Maybe have the vet check him out - you have to worry about things like luxating patellas in small dogs.