You could put the probe through a potato or wine cork to support it, then insert the end in the meatball. On a somewhat related note, my pit probe died a while back. Since I don't have a replacement, I've been clipping the food probe to the grate for the first couple hours until I get the temp stabilized, then inserting it in the food. I finally realized I could just push it all the way through the food so the end is out in the open. Then when I stabilze the temps, I just pull back on the probe til the end is in the center of the meat. Much easier that way!