Mark Appel has had a rough adjustment to professional baseball, something that is drawing concerns about his future ceiling.

The No. 1 pick by the Houston Astros last June, Appel had a solid pro debut last summer but things have gotten worse since. An appendectomy sidelined him this spring and he struggled upon his return. He has been shuffled around Houston's system as the club looks to find a comfortable place for the right-hander.

"Pro scouts who saw Appel last year and this year have generally come away disappointed," writes J.J. Cooper of Baseball America. "Appel will show premium velocity with a fastball that sits 94-95 mph and touches 97-98 mph on his best nights. But pro scouts who saw him in the Midwest League last year said that he lacked an out pitch, didn't exhibit much feel for pitching and generally didn't have sharp secondary stuff to go with his fastball."