Makes perfect sense in that he will need the run to get into game shape. The C's are about to head out on the road for about 12 days in which they play 7 games in 10 days. There won't be any practices during that time.
So if the Claws run the same basic sets as the Celtics, why not throw Rondo down there to get some run, get his endurance built up, get his timing down, and have the ability to pull himself and insert himself into the game whenever he wants.
Then about the 13th of January when the C;s start a short three game home stand, Rondo can be reintroduced to the team and start getting some big league playing time.