Lack of depth a concern for Arizona Diamondbacks' rotation

With Zack Greinke and Robbie Ray at the top and no real weak spot beyond that, the Diamondbacks might reasonably believe their rotation has a chance to be the best in the National League. The only concern is what comes after them.

With last month’s trade of left-hander Anthony Banda in the deal that landed them slugger Steven Souza Jr., the Diamondbacks depleted the depth beyond their top five starters. It had already appeared thin before that.

Of course, for most clubs, the idea of having a backlog of starting pitchers ready to step in should the need arise is more often hope than reality. Every year, only a handful of clubs have legitimate rotation depth, and those that do tend to see it…