I'm just not a big fan of Asdrubal or Rasmus in fantasy. Rasmus had a breakout season and still wasn't an impact option: 53th outfielder in standard scoring... that's especially mediocre in a 3OF format. Asdrubal is okay but if you have a good team, you'll be looking to replace him. Gray is the player Dinger may regret losing, as he noted, but he has a good stable of horses remaining and the nature of pitching makes him replaceable. If Dinger really needs a starter mid-season there will ones available and he has plenty of chips left to deal.
Sammy will win if Gray turns into a dependable #2 and Rasmus and Asdrubal plateau into solid fantasy regulars. But even then, I think Dinger would be happy with Desmond's production because it's what his team sorely needs.