I'm not doug, but he does have the glove to be an average to slightly above average CF. His arm is above average for the position and his speed is good enough to get by. (I can't believe Krivsky was so good at identifying these high talent kids soon to break out.)
His bat, though, will keep him in the majors. An 890 OPS is great, but the almost 400 OBP is what I'm excited by. He sounds like an ideal CF leadoff option, and, looking at his numbers, that's probably where his bat should be. (The number two hitter is better, but Keppinger's bat is simply better for that spot.)
Still, with Cumberland leading off, that lineup looks solid:
Cumberland CF
Keppinger SS
Bruce RF
Phillips 2B (not my call)
Dunn LF (assuming he re-signs)
Votto 1B
Encarnacion 3B
Ross/ free agent C
Makes everything else work better, IMO.