I own both Rice and Calvin in one league, and even if I were to sell "high" would it even be worth it? Move Rice for Martin + Picks? I doubt the Martin owner would even consider that.
This is why timing is so important. I've said it before, but it's worth repeating. To consistently get good value in dynasty trades, you need to be ahead of the curve. That means buying a guy like Doug Martin before he breaks out or maybe even before he's in the league. The more you wait for the player to "prove" himself at the NFL level, the higher his price becomes. So if you see a guy like Kaepernick, Shorts, or Morris putting a couple good games together, you need to immediately try to make a judgment call on whether or not he's a mirage. If you think he's legit, you need to pounce right away. I traded Rice for Richardson and a late 1st round pick (dev league) in the middle of the 2011 season. If I had waited another three months, I wouldn't have been able to get that deal. I got Shorts for Matt Barkley this year after week 7. If I had waited another month, I doubt the other owner would've accepted. There is a "buy" window for almost every player in the NFL, but it can close in a matter of weeks. Once a player proves himself, he becomes untouchable. You will not be able to trade for a guy like Martin, Spiller, Demaryius, or Kaepernick right now. You will have to pay an insane price. But there were buy windows for all of those players. You just had to be in the right place at the right time with the right vision. The ability to leverage uncertainty is massively important in dynasty leagues. Uncertainty is a dynasty owner's best friend because it is one of the only ways that he can get talent at a discount. The trick is making the right decision. That's not always easy. You don't want to give up Ray Rice for Gio Bernard just because he's younger. There aren't many players on Rice's level. If you can't get fair value, I'd probably just keep him. I know that I'm stuck with Fitzgerald in two leagues because I could never get a decent deal for him. I offered him for guys like Dez and Blackmon when they were out of fashion, but nobody budged and so I've still got Fitz. It's not the end of the world.