Mitchell, the team's top pick in the 2009 First-Year Player Draft and the club's No. 5 prospect according to MLB.com, earned rave reviews for his work in last October's instructional league and had the same positive response from those who watched him during Spring Training. But Mitchell opened 7-for-53 with 27 strikeouts for Triple-A Charlotte and was moved down to Birmingham to get back on track.
"His struggles were surprising, yeah," Hahn said. "He was in such a good spot in Glendale (Ariz.) and in instructional league. We certainly expected him to get off quick and get off well. There's a few alterations we felt in his swing that were going on in Charlotte that were to his detriment and he was having trouble correcting them.
"Again, it was more he was struggling and he looked a little different back when he was having success. It was more trying to get him back to where he was. Part of going to Birmingham was hoping to be able to iron them out there."
This oblique strain will slow Mitchell down for a couple of weeks, but the White Sox haven't lost faith in the talented athlete.
"Once he gets back from that, we are hoping he'll be able to pick up where he was at the end of spring," Hahn said. "He'll get there. We all saw it, it's in there. It's a matter of him being able to access that more consistently."
Scott Merkin is a reporter for MLB.com. Read his blog, Merk's Works, and follow him on Twitter @scottmerkin. This story was not subject to the approval of Major League Baseball or its clubs.