Lively appears to have enough deception in his delivery to offset some of the lack of tools/stuff; he may be able to sustain a back-of-the-rotation performance level. There's nothing left for him to do to improve in AAA. He's either good enough for fifth starter, or he's not.
Eflin we just don't know about yet. Post-surgery, what is he capable of? I think we'll learn a lot this summer, whether he pitches in the bigs, or in AAA.
Pivetta has the higher ceiling, but has yet to master his abilities. One can argue that improving his command/consistency is just as likely to occur in AAA as in the majors.
I think we know enough about Eickhoff; when he's sharp, he can be quite effective. He isn't always sharp, and I suspect that will always be the case - and he's not going to be able to rely on power when his command is off. Mid to back of the rotation.
Nola and Arrieta? They're ballplayers.
And then there are the young'uns!
