Below is the Jags injury report which was reported by Armando Salguero on twitter.
As you can see Mike Sims Walker did not practice. He was reported to be seen on the sideline working with a Trainer and while the Jags could be resting him I think he could be sitting out sunday. You see Sims Walker was limited in practice yesterday. He should have been able to practice today. If this was a Tuesday, I would agree they were resting him, but we are on a Thursday and usually teams want their players practicing as they get closer the game.
If Sims Walker misses Sunday's game it can be a huge advantage for Miami.