There's no good way to do it, unfortunatly. You need to yank the contents of the line without yanking the entire line qua line. Now, if 'l' were a text object for 'line' then there would be an obvious 'yil' for just getting the inner stuff, but since there isn't you'll have to do 0y$ to go to the start of the line and yank until the end of the line. That'll store the line contents instead of the line itself, so p will do what you want it to.