Teams routinely place players on waivers, even if they don't plan on trading them, so this is not an indication that the Red Sox intend to move Shoppach or Aviles. If the players go unclaimed, the Red Sox will be able to complete a trade just as easily as they could have before the current waiver period began ten days ago.
If a team claims Shoppach or Aviles, the Red Sox will have three choices. They can let the player (and his contract) go to the claiming team, they can complete a trade with the claiming team, or they can pull the player back off of waivers. American League teams will have claiming priority on Shoppach and Aviles.