Somberwald Sabertooth

You may put Somberwald Sabertooth into your command zone. You may only do that if your commander creature is not in your command zone. If your commander creature enters your command zone while Somberwald Sabertooth is in your command zone, put Somberwald Sabertooth into your graveyard.
At the beginning of your precombat main phase, if Somberwald Sabertooth is in your command zone, add one mana of any color to your mana pool.