Here's the link:
The money quotes?
"My only answer is that in a perfect world (which rarely, if ever, occurs), I prefer bringing guys up when you have the reasonable hope that they'll never go back down to the minors. That is strictly my opinion, not anyone else's. This was the case with guys like Khalil and Jake. All too often, though, you see guys come up, struggle, then go back down. That roundtrip ticket can do a lot of damage to a player's confidence, and that confidence is a key ingredient to success at the highest levels. Along those lines, think about what it did for Kouz last year when Buddy stuck with him and kept putting him out there. We all expected Kouz would hit, but I'm confident that the decision to keep him in the big leagues throughout his struggles was an element in his eventual success, even if just a sliver.
There are examples at nearly every level. During spring training of 2003, Nick Swisher was having a monster camp. After being drafted in 2002 he had finished the season in High-A ball, and the plan all winter was to start him back there. Due to his great spring, some people starting pushing for Nick to go to AA even though he didn't even have a year's worth of minor league at-bats yet (I'm sure I was one of them). I specifically remember Keith Lieppman, the Farm Director of the A's, saying, "If he goes to AA and struggles to the point where we have to send him back to A ball, I won't even know where to begin to pick up the pieces." Nick Swisher was not a guy who lacked for confidence, by the way. So, Nick started back in A ball, killed it, moved to AA, and so on."