People waaaaaaaaaay overestimate starting pitchers these days. Yes, there are some really good, top of the rotation, starters and there are team with multiple front line pitchers but most #3 pitchers aren't that good.
I mean, being #3 behind Strasburg and Zimmermann isn't exactly a mark of disrespect. I think if the writer guy had wanted to really disrespect Peacock, he would have said "back-end starter" because it seems like #5 starters are a revolving door of mediocrity. If Peacock can be on the level of a Marquis or Derek Lowe or Dempster, where he's generally average but has a couple pretty darn good years, that's a really nice thing to get I think. I'm not expecting him to bloom into an ace, unless he develops a solid third pitch.