Not quite convinced. This is something quite typical in the development of some top-of-the rotation guys, who come in, get guys out with low K rates (Hello Jon Lester, Justin Verlander and Zack Greinke, all very high ceiling guys who optimized their arsenals at the ML level and then started posting above average to elite K rates), make some adjustments and then start striking guys out to complete their development at the ML level. Bello's issues with fastball spin rate and its adverse effect on his slider are fixable. I'd say a mid 3.5 ERA guy who provides innings is his floor, not his ceiling.