Neither one had a spring training which would be a cause for concern, especially with Kimbrel. Don't really have time to let him ramp up and probably struggle in season. I get that they could send him for an extended ST and then a rehab stint in the minors but it's not the same as an actual ST and given what you would have to pay him it would be a huge risk.
I never thought Kimbrel was too smart to begin with, but sitting out the Spring proves to me that he is an idiot. Few teams are willing to take a chance on him for that reason. He was stupid to sit out Spring Training, and I wonder if he even thinks deep enough to have considered this.