re: Use Leonard as the 3rd down back and let Guice have the starting role next week.

No.

If Fournette is not back (if he doesn't have the lateral quickness), then he's a liability as a 3rd down back. He has to be able to pick up the blitz, he got embarrassed the last time he tried to do that.

I'd say give him the carries you're giving to Willliams, if you insist on him playing at less than 100%. He can blast into the line still, and if he hits a crease (and doesn't get ankle tackled) he will make some big gains. Open field, he's never been about moves, he's a straight line runner, so if he clears the line he will do well.