I heard you never refreeze meat after it thaws unless you cook it first. I probably would have heated up the grill when I discovered the meat and had a feast.
On that note, I'm going to give you my recipe for sliders. I buy beef from the Fresh Market weekly when they run their ground chuck sale here. (had these yesterday).
Basically, rather than grilling the burgers, I use a nonstick ceramic skillet. I use the wrapping paper the beef comes in, but you could use foil or whatever.... Roll or use your hands to flatten the meat to a consistent thickness in the shape of a big square or rectangle. Then use a table knife to score the meat into small squares. If you have slider buns, you can size them appropriately...you can also cut hot dog buns into halves and make them that way.
Position the burgers in the pan and sprinkle with a little kosher salt....then hit each burger with a shot of Worcestershire sauce. I buy a large container of dehydrated onions and sprinkle those over all the burgers. After you get them lightly covered with onions and salt and Worcestershire sauce you let them cook a minute or so....flip them and add about a half cup of water to the pan and cover.
When the burgers are cooked, you can take slices of american cheese and cut them into quarters...that makes just about the perfect size slices for the mini burgers. Once the cheese melts, you put them on buns and you're ready to serve them.
I make those for my kids weekly and they eat them up. They never were big on burgers until I started making them...