Hector: I think that the strategy to promote too soon has backfired greatly with Antonelli, Headley and LeBlanc.
Careful with Blanks...
It's always a tough balance.
Antonelli blitzed through HA and AA before struggling last year at AAA. In hindsight it may have made sense to leave him at AA at the beginning of 2008, but he certainly appeared ready for the PCL.
Headley was a very different case. He had a full year in HA Lake Elsinore, a full year in AA San Antonio and nearly 300 pa's in AAA Portland. That's not really an accelerated progression. In fact, what was keeping him down in AAA more than anything was the fact that he was learning a new defensive position.
Leblanc pitched about 150 innings between HA and AA and now has almost 200 in AAA. That isn't terribly unusual for an advanced college starter, and he's still in the development process now.
The other thing, and possibly more importantly, is that sometimes guys need to be pushed in order to progress. For instance, had we left Leblanc at AA he could have continued to get everyone out with his changeup without needing to locate his fastball effectively. He needed to get to a level with more advanced hitters that would force him to make an adjustment to his game. Similarly, Chase had a .939 ops in AAA after having a 1.023 in AA, so he needed to start facing ML pitching in order to keep getting better.
Remember, regardless of the preparation they receive in the minors, young players will almost always struggle early on in the Majors, often for two or three seasons, before hitting their stride. Adrian Gonzalez hit .229/.272/.401 in 2004 and 2005 combined for the Texas Rangers, and there are countless other examples. Just like any other job, there's only so much you can do to prepare before actually doing the job.